Time Machine Migration Question

I am in the process of moving my Time Machine from a USB attached drive to a NAS.  I am looking to do the initial backup on the NAS and was presented with the option of replacing the USB drive with the NAS or alternating between the two.  My USB drive is 90+% full which is why I'm looking to move it, but I hadn't considered alternating would be an option.  Because I am new to the NAS realm, and am always looking for a fallback, I was wondering if alternating is a good idea.  Or, if I just say replace, can I get the USB drive back just by selecting it. 
Thanks in advance as I just looking for a couple of answers before diving in.
Thanks.

As your USB drive is nearly full, I do not think it is a good idea, and if you do it, you will first need to format the USB drive to be able to store more backups.
On the other hand, alternate backups will allow you to have backups in different drives, so if one of them fails, you will still have backups in the other one, so in this case, you should do it. It is safer.
See > http://pondini.org/TM/34.html

Similar Messages

  • Error "The Connection Failed" in Time Machine, Migration Assistant and Restore From DVD

    I am receiving this error when trying to connect to my Time Machine Backup in my Time capsule. I input the proper password to access my Time Capsule and It returns me to the screen with the caption "The connection failed" under the Time Capsule name in the "Select your Disk" screen. What would cause this error. I am connecting via WIFI (AirPort) and have full signal. I am using Mac OSX 10.6.8
    I recently had my 1TB hard drive replaced and I am attempting to restore using Time Machine, migration assistant or from the startup dvd (tried multiple ways, no success). The initial setup of mac OSX 10.6 would not let me connect or other attempts after erasing hard drive and reinstalling OSX from disk.
    Worked on it all weekend and don't have enough beer to drown the frustration, any help is appreciated.

    You are correct TM is not at all easy to do a full restore.
    To answer your question: Yes TM disk does show up in finder.
    After my initial startup setup I was able to start TM and access all my previous backups. I migrated some files and was able grab the data from finder. Not satisfied with that I tried to do a restore to that previous date, to no success. I then erased the HD and reinstalled OSx and tried again from the setup screen. That didn't work, sulked over some beers. I then tired with Migration assistant...same result (more beer).
    In starting TM after trying MA, only one backup was showing in the Star screen (today). None of my previous backups were showing. Since exiting TM it has been "Making Backup Disk Available" ( xGB of 6.29GB). Considering the size, I can only assume that these are my previous backups.
    I have reviewed Pondini's posts, FAQs, and tutorials. I am a little scared to try and locate the drives through Terminal as in Pondini's TS #6 guide. If I can get my previous backups to show up, I will be happy with dragging files from Finder to restore my data and slowly work at restoring my settings/applications.

  • Migration assistant from Time Machine - more questions

    I have recently used Time Machine with Migration Assistant to transfer account information from an old iMac I am decommissioning. At first, I decided to simply transfer account information documents, and not any programs. However, after completing the Migration, I tried to use it again to copy across programs. However, the second time I used it, the Assistant did not recognize the Time Machine backup for the old iMac (even though the sparsebundle exists). Furthermore, when the older iMac began its Time Machine 'cycle' (eg, it has not been fully shut down yet), it did not recognize this bundle either, and created a new TM backup.
    Can anyone help? I am most concerned with ensuring I have what I need on my new computer. But also would not want to have to get rid of the old sparsebundle, as it might contain information I need in the future.

    Have you run any backups of the new Mac? If so, how did you answer the "Re-use" prompt, per #B5 in [Time Machine - Troubleshooting|http://web.me.com/pondini/Time_Machine/Troubleshooting.html] (or use the link in *User Tips* at the top of this forum).
    It sounds like you did, and selected "re-use." If so, that may be the problem. The old sparse bundle was "converted" to belong to the new Mac, so all the new backups belong to it.
    That would also explain why backing-up the old Mac started a new sparse bundle -- the old one is now associated with the new Mac, not the old one.
    Migration Assistant uses the last backup from the sparse bundle you select; you can't pick and choose which one you want.
    Your best bet may be to use the +*Browse . . .+* option, per #17 in [Time Machine - Frequently Asked Questions|http://web.me.com/pondini/Time_Machine/FAQ.html] (or use the link in *User Tips* at the top of this forum). See if you can find the last backup of the old Mac. If so, you should be able to selectively restore from it. You'll need to restore to an "alternate location;" see #15 in Troubleshooting.

  • What to do after Time Machine migration (how to start using TM again)

    Hello,
    I have just restored my system from my Time Machine (TM) backup (I have a USB hdd plugged into my airport extreme (AEB), so the TM backup is a sparsebundle file on the USB hard disk).
    The initial setup with migration assistant did not work - it could not find the sparsebundle on my hard disk (this was with leopard 10.5). After setting up a dummy account and doing a system update to 10.5.6 migration assistant then worked fine.
    My question is how do I start doing TM backups again? If I am logged in as the user who was restored via migration assistant and then enable TM and then select the HDD that is shared over my AEB will it automatically recognize the old sparsebundle and use that as the starting point for backups? Or do I need to delete the old sparsebundle and then start a brand new backup?
    My external HDD is not big enough to accomodate an additional backup, and so I would prefer to just use the existing backup if possible.
    Thank You!

    atticus_pf wrote:
    Hello,
    I have just restored my system from my Time Machine (TM) backup (I have a USB hdd plugged into my airport extreme (AEB), so the TM backup is a sparsebundle file on the USB hard disk).
    The initial setup with migration assistant did not work - it could not find the sparsebundle on my hard disk (this was with leopard 10.5). After setting up a dummy account and doing a system update to 10.5.6 migration assistant then worked fine.
    My question is how do I start doing TM backups again? If I am logged in as the user who was restored via migration assistant and then enable TM and then select the HDD that is shared over my AEB will it automatically recognize the old sparsebundle and use that as the starting point for backups? Or do I need to delete the old sparsebundle and then start a brand new backup?
    My external HDD is not big enough to accomodate an additional backup, and so I would prefer to just use the existing backup if possible.
    not possible. TM will make a complete new backup after a new install and there is no way around that. if your existing backup drive is too small for that you have to delete the existing backups and start TM backups from scratch. (just thrash the sparse bundle and empty trash).
    Thank You!

  • Restoring From Time Machine Migration Assistant (and other ??)

    Hello
    Please bear with me on this long question....
    For several reasons I reinstalled ML which involves erasing the HDD first.  I do have everything bakced-up to Carbonite and TM.  Carbonite is slow as molassess so I opted to try Migration Assistant/TM to restore my files.  MA does not allow you to choose an older (good) backup and the backup that was used was an incomplete one as evidenced by the photo library being incomplete.  Another poster had a similar question and the solution involved using the install disk.  There is no install disc since it was a download from the Apps store. 
    Carbonite has a tendency to freeze-up during a long download.  Restarting it brings your download back to the very beginning.  I'm not happy about Carbonite.  I've heard of SuperDuper and seems to have gotten good reviews.
    Questions:
    1.  Is there a method to access an older TM backup from MA?
    2.  Is there a better option that Carbonite?
    3. Is SuperDuper a good option for backups?
    thank you, Bruce.

    If your Mac shipped with a System Install DVD then boot from it and choose "Restore from Time Machine backup".
    If your Mac shipped with Lion already installed you should be able to use OS X Recovery. Boot while holding ⌘ R and choose "Restore from Time Machine backup".
    Either one should present a dated list of complete system backups from which to choose. Ideally it should be the most recent one, but if you have reason to believe it is incomplete (it should not be) then try an earlier one.
    You can also boot from a locally connected Time Machine backup volume. Make sure it is connected with USB or FireWire and boot while holding an Option key. This will invoke Startup Manager, from which you can select your Time Machine backup volume. It will present the same restore options as OS X Recovery.
    These options will be faster and should be less prone to difficulty than using Migration Assistant.
    Time Machine and "clone" software use very different philosophies. SuperDuper! is good, so is Carbon Copy Cloner. They are more customizable than Time Machine, whose customizable features essentially consist of an "on / off" switch
    Of course that is also its sole advantage over the others - it's boneheadedly simple to use.
    Forget Carbonite, as you learned it does not work well on Macs. I know of no similar offsite backup services to recommend.

  • Does Time Machine/Migration Assistant successfully transfer software licenses for Microsoft Office and Adobe?

    I have a MacBook that I purchased in late 2007.  It's been very good to me over the years.  However, I'm been having various minor issues, and tonight I noticed that the screen goes to black at about 45° as I'm closing my laptop.  In other situations I'd try to fix this myself, but right now I'm a Peace Corps Volunteer in rural South America and have limited access to the right tools, much less replacement parts.  So instead I'm taking it as a sign that my trustworthy companion is about to give up the ghost and I should get a new computer now, instead of completely running this one into the ground and potentially losing important documents, photos, &c.
    My question is simple:  Does Time Machine and/or Migration Assistant successfully transfer licenses for Microsoft Office 2011 and for Adobe software?
    My software installation disks are in a box in a basement in the United States.  And since I'm not quite sure which box it is (last summer I did not see the need to label my own boxes), I'm not going to ask some unsuspecting friend or family member to dig through all my posessions to find an alphanumeric code or two, especially if I can just transfer/migrate the license without it.
    Many thanks.

    Try the combo update on the old machine.
    10.6.8 Combo Updater
    If the 2 computers have the correct cable connections, try the Target Disk Mode.
    Target Disc Mode

  • Split Time Machine migration over 2 volumes?

    Hi,
    I've just bought a shiny new MBP with 128GB SSD, which I am migrating to from an iMac.  I have my Time Machine backup of the iMac (which I've sold).  The iMac had just under 1TB used all-in.  My intention is to keep the OS and apps on SSD and keep my photo, music and video libraries onHDD.  My question is how do I split out my apps and settings vs the user data in my time machine backup and migrate them to the right volumes?  I have an external Firewire hard drive and also an optibay HDD kit on its way.  If I need to temporarily restore the whole thing to one volume and manually move things around I have the scope to do that also.
    Thanks.
    EQLZR

    Found this on MacWorld which looks pretty straight forward.  I'll give this a go:
    A brief tutorial on symbolic links 
    Nov 06, '01 10:29:06AM • Contributed by: jmil
    OS X's file structure mounts all partitions under the "/Volumes" directory at the root level of the filesystem. However, when navigating the filesystem with "cd" and other commands, it can be annoying to type "/Volumes/volume_name" each time you want to access a different partition. To learn about symbolic links and use them to add shortcuts at the root level of your filesystem, read the rest of this article. This assumes you are moderately comfortable in the Terminal, and that you have administrative privileges.
    What is a Symbolic Link?
    If you've ever made an "Alias" to a file in classic Mac OS, or a "Shortcut" to a file in Windows, you will easily be able to understand the UNIX equivalent (where "aliases" and "shortcuts" came from in the first place!), called a "Symbolic Link". The easiest definition to understand is directly from the man page, "[A Link] is useful for maintaining multiple copies of a file in many places at once without using up storage for the 'copies'; instead, a link 'points' to the original copy." (If you want to read more about it, type man ln in the Terminal.)
    Let's say you have two partitions or drives - "X" containing OS X and "Classic" containing OS 9. To navigate to "X", you simply type
    cd /
    To navigate to "Classic", though, you'd have to type
    cd /Volumes/Classic
    If you have many partitions and/or drives, and you are trying to manage many files across them, it can get annoying to type "/Volumes" every time. Moreover, you cannot simply create an Alias to the drive/partition to accomplish this because the command line utility "cd" does not handle Mac OS aliases properly. However, a symbolic link will solve the problem.
    To create the link, simply type the following:
    cd /
    ln -s /Volumes/Classic/ Classic
    That's it. ln -s makes a new file called Classic which points to /Volumes/Classic/. To see that this worked, you can simply type
    ls -la | more
    (note the "|" character is called "pipe" and is found above the "Return" key). You should see a line with the following text:
    Classic -> /Volumes/Classic/
    The arrow shows you exactly what you did... A file named Classic points to /Volumes/Classic.
    Links have many possibilities around the filesystem, and I encourage you to read more about them in the man page. While command line utilities cannot recognize Mac OS aliases, the Mac OS Finder will recognize symbolic links you construct in the terminal, or via Third-Party Utilities such as SNAX so you can use links just like aliases in the Finder.
    Jordan

  • Time Machine, Migration Assistant, and a BIG headache

    Set up my new rMBP from a time machine backup on external and worked great. I removed some applications from the dock that didn't transfer over successfully (i.e. Word 2004). I didn't include iTunes during the transfer.  Once time machine restore was complete, everything on the rMBP worked great.  I wanted to get my iTunes from the external and so I used the Migration Assistant to copy over JUST the music.  I unchecked all the boxes except Music.  Took over 1 hour just to copy over 30GB of music and so I was suspicious...
    After completion, I see that it copied over my music, BUT
         - all Documents gone
         - applications previously deleted WERE BACK (i.e. Word 2004)
    Went back to my old 2010 MBP to do another time machine backup, and signed into Mail....
    Signed into Mail on the rMBP....
    Got an email that my apple ID was used to sign into iCloud....
    Then now rMBP Mail can't access ANY of my email accounts....
    What in the world happened?  I just wanted to copy over my Music and now it's a BIG headache.....
    I knew I should have avoided Migration Assistant and should have transferred over Music upon initial setup of the rMBP....
    Tried to restore the rMBP from time machine but cannot b/c the time machine backup was done under snow leopard....
    So uninstalled Mavericks and reinstalling....1 hour wait to download...
    Then (hopefully) will restore from time machine (make sure to include Music this time)....which takes about 2 hours....
    So 3 hours just to get Music, when it should just be a simple copy/paste job....
    On the bright side, I got a Samsung display and so I'm happy with that...the display is sharp, evenly bright, and no creaking case

    Hey hp12c,
    Thanks for the question. The following article may provide the information you are looking for:
    Mac Basics: Time Machine
    http://support.apple.com/kb/HT1427
    Restoring specific files or folders
    Choose Enter Time Machine from the Time Machine menu and the restore interface appears. You can literally see your windows as they appeared "back in time."
    You can use the timeline on the right side of the window to reach a certain point back in time (the timeline shows the times of all backups on your backup drive). If you don’t know exactly when you deleted or changed a file, you can use the back arrow to let Time Machine automatically travel through time to show you when that folder last changed.
    Note: Dates in pink indicate the data resides on your Time Machine backup device. Dates in white indicate the data resides on your Mac. In OS X Mountain Lion and Lion, portable Macs have the feature of local snapshots. See this article for details.
    You can also perform a Spotlight search in the Time Machine Finder Window search field to find a file. Simply type the Spotlight search field and use the back arrow to have Time Machine search through your backups to find what you are looking for.
    Before you restore a file, you can also use Quick Look to preview a file to make sure its the one you want. Highlight the file and press the Space Bar to bring up a quick look.
    To restore, select the file/folder and click the "Restore" button. The file will automatically be copied to the desktop or appropriate folder.  If the file you are restoring has another file in the same location with the same name, you will be prompted to choose which file to keep or keep both.
    Thanks,
    Matt M.

  • Time Machine Migration Assistant?

    Right now I'm running on an old white model macbook and plan on buying a 27" iMac tomorrow and was wondering if I was to use migration assistant with my time machine back up would that over write everything on the new iMac? like the iLife '10 suite?

    Well first you would probably not be running Migration Assistant, when you turn on the new machine for the first time it will launch Setup Assistant and part of that is asking if you are transferring from another Mac. Simply follow the on-screen instructions and you should be set.
    However to answer your question neither Setup Assistant nor Migration Assistant will not overwrite newer software. For example the new iMac has ILife 11 (there is no such thing as iLife 10) on it and the old machine uses iLife 09 (or earlier) the Assistant is smart enough to detect which is the newer version and leave it where it's supposed to be.
    Roger

  • Time machine migration when apps on new computer are later versions

    I have a time machine backup of my old macbook, just got a new one and it comes with iLife 11 preinstalled. I don't want these apps to be overwritten with my older (iLife 09) apps.
    Should I rename them first, or delete the older apps off of time machine or is there any other way to make sure I don't get these overwritten.
    (I imagine the iLife apps must be on the install disk in case I do have to reinstall iLife 11), but I don't have that currently, it was all installed at the university - hence I just want to know the quickest way to do this
    Thanks!

    Pete Thomas wrote:
    My problem was that I asked a specific question and was directed to an FAQ that was a different, much more general question:
    Take a look at your first post -- there's no mention there that you'd done any research at all, or whether you'd already started up the new Mac. And it ends: "I just want to know the quickest way to do this."
    "How do I set up a new Mac from my old Mac or its backups?" - not what I asked. FAQ 19 is mostly about how to use set up assistant which I already know and is irrelevant in this case as the installation had already taken place and therefore I cannot access Set Up assistant
    You didn't mention any of that.
    so the FAQ was telling me to reinstall or create a temporary account, time consuming and not very helpful when all I needed to be told was "you can run migration assistant and it will be fine", which was the very helpful and speedy advice I got elsewhere.
    Again, that was far from clear in your first post. And the next sentence starts "After your Mac is up and running, you can use the similar Migration Assistant ..." with a link to that page. Many, many people start up their new Mac, skip +Setup Assistant,+ and create a new user account, and use it for a while. Then they run Migration Assistant and wonder where all their data is, and once they find the migrated account, want to consolidate the two. We see those roughly once a day.
    After reading all the way to the bottom, there is a sort of answer to my question:
    "Note that Setup Assistant is smart enough not to replace newer Apple apps that came with the new Mac with older versions from the old Mac or backups."
    But then a caveat that confuses the whole issue for me:
    "In some cases, there may be a few exceptions:" followed by lots of links to follow.
    Should I have just ignored the fact that some apps aren't compatible with Snow Leopard? Or that in some cases you may have to re-enter serial numbers?
    It would have saved us a lot of time, if you know the direct answer to the very specific question to say what the answer is rather than "read the FAQs". I'd already done a search to see if my question was frequently asked, and it wasn't.
    Again, had you indicated that . . .

  • Time Machine/Migration Assistant issues

    I just bought a MacBook Pro, and my old computer is a PowerBook G4. I did a Time Machine backup of my old computer onto an external hard drive, then used Migration Assistant to transfer the Time Machine backup from the external drive to my new computer. I had a few files saved on the new computer before I transfered from my old computer, and those seem to be gone now. My question is: when a Time Machine backup is 'migrated,' does it delete everything first?

    horseymichelle wrote:
    I just bought a MacBook Pro, and my old computer is a PowerBook G4. I did a Time Machine backup of my old computer onto an external hard drive, then used Migration Assistant to transfer the Time Machine backup from the external drive to my new computer. I had a few files saved on the new computer before I transfered from my old computer, and those seem to be gone now. My question is: when a Time Machine backup is 'migrated,' does it delete everything first?
    no, migration does not delete anything. you are just logged in as a different user now which is why you don't see those files. log out of the migrated user and log into the user you originally created on the MBP. those files are there. I suggest you move them over to the migrated account as most of your stuff is in there.

  • Read only access issue after time machine migrate

    Having a small issues on my new rMBP. I recently switched from my MBA to this newer rMBP and I previously had a Time Machine backup that I migrated over. For some reason though..when accessing my external hard drive it keeps asking to authenticate the user and I have to put in a password anytime I edit or add files to this external drive. I was also having issues running some commands in Terminal where it said I didn't have access..my current user shows up as being admin but I'm not entirely sure how to get past all these restrictions and have read/write access  to everything.

    So I looked at the above images and noticed that the disk labeled "HD-PATU3" is almost entirely full - only 5GB of 1TB is available - so it's essentially "full".
    You said that this drive "was" used for Time Machine backups - is that still what you want to do with it in addition to your own files? If you do still want to use as TimeMachine that's OK, but you can't predict what TM will do with it as far as space goes unless you split the disk into two partitions. TM knows how to remove old "snapshots" to make room for new backups, but do you need space on there as well for your own stuff?  Some people think it's not a good idea to mix your own stuff and TM stuff on the same disk volume, so that has to be your decision to do.
    You might want to take a look at http://pondini.org/TM/6.html and read what he has to say (Pondini is a TM expert/god/phsychic - basically he recommends splitting up the drive into two partitions - one for TM and one for you - that way things are easier for your data as you don't have to live with issues the TM enforces on it's backup volumes. So answer the questions:
         1. how large is the internal drive on the rMBP?
         2. how much do you want the external drive to have for backups and your stuff - in fact is there a reason why you don't have all
             stuff on the internal drive? There are performance penalties for having your data and TM backups on the same disk. You
             probably have a nice large internal disk on the new rMBP so is this really what you want to do?
         3. Depending on the answers we can get more specific to solve your issue(s)
    later......

  • Time Machine Migrate

    Hey there!
    I just migrated from my old macbook pro to my new macbook pro.
    i wanted to know now, when i plug my time machine drive into my new mac it doesn't detect it as my time machine device like my previous machine. do i have to "re-sync" it with my time machine and start new backups or how will it detect just to back up from my new machine?
    much appreciated,
    D

    There's another consideration besides TM starting a new set of backups.
    Your old backups are now "stranded:" since they're from a different Mac, TM on your new Mac won't delete the oldest ones from your old Mac when it needs room for new backups.
    So if your TM disk isn't well over twice the size of your data, your best bet may be to simply erase the TM drive via Disk Utility (in your Applications/Utilities folder) and let TM start fresh. Do *not, ever* move, change, or delete any TM backups via the Finder. If you want to keep, say, your last backup for a while, use the procedure in item #12 of the Frequently Asked Questions *User Tip* at the top of this forum.
    Also, you won't see the old ones when you +Enter Time Machine+ on the new Mac; you'll need the (badly-named) +*Browse Other Time Machine Disks+* option. Hold down the Option key while clicking the TM icon in your Menubar, or right-click the TM icon in your Dock.

  • Snow Leopard Time Machine process question/possible problem

    For starters I want to say that I am not dealing with my own machine, but a friend's, so there's some missing information. Any help would be greatly appreciated!
    Ok, so my best friend bought a 15" MBP thru me during my short time as an Apple retail employee, which is how I got called in to "fix" it, although I'm still better with PCs than Macs. Anyway, it was purchased around December 2010, has at least Snow Leopard, intel i5 processor, 500 GB HD, not sure if 5000 or 7200 rpm, 4GB RAM. A day or so ago it started acting "weird" he says, like when closing google chrome the color wheel spun forever and took forever to close, and from then on every program acted the same; took forever to open and close. He said it was like there was some major process running in the background that was just using up all of the RAM and processor, leaving him with nothing to use for anything else. He shut it down and restarted it several times, but it acted the same. Sometimes he'd even have to force power it down. He then decided to do a wipe and restore with Time Machine. Thanks to google images I know for sure that he went thru all the bs with selecting what exactly to do, what restore to use, and where to install it, and that the transfer screen with the finder-to-fnder-like image and the progress bar appeared and completed fully before it automatically restarted itself. White screen with Apple logo appeared, he heard the boot up chime/BONG/WALL-E noise before the spinner wheel came up under the logo, which is where it stands now.
    The only question/concern is that it has been here for 10 hours, literally. Now the spinner is STILL spinning, that has not frozen that either of us are aware of, but both of us being so new to Macs we are completely unsure if it's ok. I did some online research and I've seen where people have had their macs freeze on boot up, but they usually don't chime; or it took like 14 hours to do the entire restore process, but they were significantly older and slower machines. Like I said, this could be status quo for this process, but I honestly do not know that. Feel free to just say "depending on the amount it's restoring, it could very well take that long, be patient" if that's the honest truth. I'm looking for verification.
    PS - his time machine backup is on an external USB hard drive, which is plugged in, and it's from November as he forgets to plug it in, but he has like photoshop and aperture, takes lots of pictures (yes we know those since November are gone), and honestly is on his MBP so much the only way I can think to describe it is that he literally uses it like a cheap whore.
    Thank you all!

    delete all drivers using the correct un-indtstall software, re-instalthe mac softeware and in stalll. GO TO SYSTEM PREFS, and select the printer and add the printer to the left side for install
    , then select that partictular printer.

  • Mac air with external hard drive - not being found on Finder, Time Machine, Migration Assistant

    I have been using an external drive (Imation Apollo) to access only, old files from previous computer (PC) on a new Mac Air.  I had not transferred them across to new computer (didn't want to do that)  just accessing them from the HD.  It had been working fine until recently.  Each time the external drive had been connected Time Machine would come up and ask if i wanted to use this drive for back ups, and I always chose 'Decide later'.  So, as yetI hadn't as yet configured Time Machine to do back ups.
    Recently I noticed that the extrnal HD was no longer showing up on Finder.  Slight panic as i have 5 or 6 yrs of work saved on that HD
    Further investigations - it's also not showing up either on on Disk Utility, or on Migration Assistant.
    I've done the following: 
    Tried HD in each of different USB ports  - made no difference, HD still not showing up
    Tested different Hubs in each port with HD attached - no difference HD not showing up
    Tried USB flash drives in the USB ports - These are working fine and show up on finder
    Tried the HD on other comptuters (a PC though, don't have access to another mac to do this test)- working fine, the HD is showing up and is accessable
    Interrogated the Console logs to try to see if the act of attaching the HD creates a log entry - couldn't find anything
    Rebooted computer via shut down, power disconnect - no difference
    Reset PRAM - no difference still not showing up
    Reset SMC - no differnce still not showing up
    So I think I have established that all the USB ports are functioning correctly and able to access other external drive devices, using hubs with external powersource is not the issue, identified that the external hard drive is working OK, and it appears that the Mac itself is functioning normally.
    What would be the reason the Mac now does not allow this specific external HD to be identified and accessed.  The only possible things I can think of are
    if I had in fact pressed 'Do not use' when Time Machine asked 'do you want to use this drive for back ups'.  Would that mean that the Mac now totally rejects this HD from being a source of accessible files - I hope not!
    I also think that my husband may have disconnected the hard drive from my computer to access some stuff and he just yanked it out rather than use the safe eject method.  Could this create an issue?  The Hard drive works fine on his PC.
    Why is my Mac Air now rejecting this HD and what can I do to access my historical files now. 
    Any assistance anyone can provide would be very greatly appreciated!
    Thanks
    Anna

    I can't answer why it isn't accessing it, but I have a slightly related issue w my back up drive starting to get noisy.
    Realizing that redundancy is safety for critical data.  I talked to my brother about my situation the other day & he said he has 3 small Western Digital portable HDs that he rotates for backup. He even keeps 1 in the safe deposit box.
    I have read for some time that we should have multiple back ups & also have our critical stuff backed up off site. Amazon HD reviews had a woman telling about how she was very backed up on multiple computers & hard drives, but they were robbed or burgeled & all of them were stolen including her thesis that was on the computers.
    Hard drives aren't that expensive. I just bought a new Western Digital 1 TB drive for $89.99. I plan to use it to back up the Seagate that is getting noisy & then maybe alternate them.
    Also, when I came back to Mac, I moved practially all of my documents to Mac. I think I just dragged & dropped or something. Photos, Office, & pdfs do fine that way. & then you could back them up to a couple of different external drives & remove from your MacBookAir.
    Unfortunately I think most of us do not back up until crisis & then it may be too late.
    Also use Time Machine. For the 1st time in my computer life, my computer is well backed up--although now realizing the need for redundancy so will start backing up to at least 2 different HDs alternatly.
    So, not sure why it isn't working & hopefully you have come up w a solution by now.
    I think what I would do in a situation like this, since you can access it on the Windows machine would be to transfer the data to the Windows machine & then transfer it back to a different back up.
    I'm looking into backing up what I still have in Windows using a thumb flash drive. I think it should all fit ok now that they have the larger drives & I don't have very much left in Windows format.

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