Does time machine do incrementals backups or full backups each time?

does time machine do incremental backups or full backups each time? in other words, is it only backing up changes or everything that itis told to backup?

+is it only backing up changes or everything that it is told to backup?+
Time Machine makes physical copies of new and changed files for each backup but it just establishes hard links to files previously backed up that still exist on the source rather than making new copies of them.
This Ars Technica article explains how the hard links work.
http://arstechnica.com/reviews/os/mac-os-x-10-5.ars/14

Similar Messages

  • Time Machine will not do a full backup when set up

    I am trying to set up time machine for the first time on a external HDD, but it just won't do a full backup in the first time I set it up, I knew I had a problem when I entered the time machine and it would only show today and now, I had the time machine set up for about a week. I already checked the time machine options and it says full backup should be 178 GB, but when I set it up it does not do the full backup just a partial, the time machine disk is always empty, I see no errors in the time machine preferences and also formatted the external HDD the HDD Mac OS Extended, Mac OS Extended (Journaled), Mac OS Extended (Case Sensitive), Mac OS Extended (Case Sensitive Journaled) and even tried a different HDD and I always get the time thing, no full backup when I set it up, also fixed permissions on all my disks and no luck... can anyone help???

    this is the message I got;
    Starting standard backup
    Couldn't find en0.
    Unable to determine UUID for host. Error: 35 Resource temporarily unavailable
    * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[NSCFArray initWithObjects:count:]: attempt to insert nil object at objects[0]'\n* Call stack at first throw:\n(\n 0 CoreFoundation 0x00007fff833c05a4 __exceptionPreprocess + 180\n 1 libobjc.A.dylib 0x00007fff887d2313 objcexceptionthrow + 45\n 2 CoreFoundation 0x00007fff8336b317 -[__NSPlaceholderArray initWithObjects:count:] + 407\n 3 CoreFoundation 0x00007fff8337fc68 +[NSArray arrayWithObjects:count:] + 56\n 4 CoreFoundation 0x00007fff8338adb1 -[NSArray arrayByAddingObject:] + 193\n 5 backupd 0x000000010000989b 0x0 + 4295006363\n 6 backupd 0x000000010000a510 0x0 + 4295009552\n 7 backupd 0x0000000100006d00 0x0 + 4294995200\n 8 Foundation 0x00007fff80f04f65 _NSThread__main_ + 1429\n 9 libSystem.B.dylib 0x00007fff80876f66 pthreadstart + 331\n 10 libSystem.B.dylib 0x00007fff80876e19 thread_start + 13\n)
    terminate called after throwing an instance of 'NSException'
    2009-11-08 22:50:42.463 ReportCrash[235:2503] Saved crash report for backupd[146] version ??? (???) to /Library/Logs/DiagnosticReports/backupd2009-11-08-225042localhost.crash

  • Time Machine wants to do a full backup.  How do I point it to my previous backups so it will do an incremental backup?

    I lost my wireless connection to my backup drive for a short time.  Now time machine wants to do a full backup.  It doesn't know that I have previous backups.  How do I point it to the previous backups so that time machine continues to do incremental backups rather than doing another full backup.

    I did some more reading and I found that Time Machine would find the older backups once a new backup is completed.  The backup ended up being a little larger than previous backups (2.65 GB vs typical incremental backups of several MB's)  but when it completed, time machine updated the last backup time/date and the oldest backup time/date properly.  So I guess, I don't have a problem.

  • I recently did a full reinstall from my time machine and now my MacBook pro won't back up to the time machine. It starts a full backup ignoring the original back up, can anyone help?

    I recently did a full reinstall from my time machine and now my MacBook pro won't back up to the time machine. It starts a full backup ignoring the original back up, can anyone help?

    Did you follow the instructions on the page linked below?
    OS X Yosemite: Recover your entire system

  • Time machine, did it perform a full backup?

    A bit new to this. Upgraded to a new MBPro retina, mt lion from an older MBP using migration assistant.
    After all was finished and all the files were on my new machine (I did not use Time machine to migrate or backup to the new mac, I used migration assistant), I connected to time machine to perform a completely new backup of the new machine. I have 295GB to copy over. So, it seemed to take forever. I was on day 2, noticed all the threads about the slowness, but then the new machine froze. It said it was around 170GB through it. I could have also had a bit of interuppted internet too in that time. I also could not access the internet on the new machine at all by that point. So, I rebooted and I assume by finding the disc and starting again, it looked like it picked back up at roughly 125GB. that took about 6 hours or so. So, I think that roughly it may have gotten the whole 250 gb but not sure.
    Also, on my select disc option I have two listings for my time capsule now. Not sure if that makes a difference.
    My question really is how can I see what exactly went through? I have entered time machine but can't tell really if everything in those files copied. Can I at least see the size of the backup on time machine? I would even be willing to do a forced full backup again of all 295GB, but can't seem to see how to do that.
    I am a bit new to this part, so sorry if I am asking really obvious questions. I just didn't want to find out at a later time that I only have partial backups. Thanks for any advice.

    Launch the Terminal application in any of the following ways:
    ☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
    ☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
    ☞ Open LaunchPad. Click Utilities, then Terminal in the page that opens.
    Drag or copy — do not type — the following line into the Terminal window, then press return:
    sudo tmutil compare
    You'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up.
    The command will take at least a few minutes to run. Eventually some lines of output will appear below what you entered.
    Each line that begins with a plus sign (“+”) represents a file that has been added to the source volume since the last snapshot was taken. These files have not been backed up yet.
    Each line that begins with an exclamation point (“!”) represents a file that has changed on the source volume. These files have been backed up, but not in their present state.
    Each line that begins with a minus sign (“-“) represents a file that has been removed from the source volume.
    Files that you’ve excluded from backup, or that are excluded automatically, are ignored.
    At the end of the output, you’ll get some lines like the following:
    Added:
    Removed:
    Changed:
    These lines show the total amount of data added, removed, or changed on the source(s) since the last snapshot.

  • Time Machine don't make a full backup

    I just started with Time Machine. I made my first backup with a USB cabel of my Mac book Pro (28 gb used) but the Time Machine folder is only about 22 gb - how can that be?
    Time Machine haven't come up with any errors but I think there is something wrong anyway.
    Do one of you have any ideas?
    Thanks in advance
    /Kudsk

    My first backup was with a usb cable but then I went wireless I wanted to use Time Machine but this time it made a new file called "Lars Kudsks computer_001b63b12c5a.sparsebundle" instead of using the "Backups.backupdb" folder. - How can that be?
    And my mac book pro only finds the external drive if I open the Finder window (and in some way show "Time Machine" where to find the external drive - if you understand what I mean).

  • Time Machine Has Never Performed a Full Backup that Can Be Restored From

    I've been backing up my system via time machine to a time capsule. I'm using the same time capsule for both my mac and my wife's. My wife's mac is backing up fine with numerous full backups that can be restored from. However, when I recently booted into recovery mode, I discovered there were no full backups of my mac that I could restore from. I've been using this time capsule for about a year now so I'm concerned as to why there are no full backups. I can enter time machine and see my docs and files...just no full backups. Thanks for your help.

    There was a bug in Mountain Lion that caused TM to fail to backup system files.
    See D10 here. http://pondini.org/TM/Troubleshooting.html
    Honestly if you want a reliable full backup get CCC or other clone type backup and do a disk image to a USB drive that you can then test boot from. Then use TM for incrementals..
    What the change to Maverick will bring I am not sure.. ??
    We went from big cats to card sharps in Westerns..
    http://en.wikipedia.org/wiki/Maverick_(TV_series)

  • Time Machine doesn't do a full backup

    Hi there,
    I have a 320GB external hard drive I use as a Time Machine backup. This has always worked before.
    Recently I reformatted it and made a small partition (70GB) for other bits and bobs. Now though, whenever it backs up only a few KB of data seem to change, nothing I add or delete on my MacBook HD gets backed up to the external drive. Which is worying!
    There's ample room in the backup partition to add the updated files, but it doesn't.
    I've troubleshooted it, done a full reset etc, but I can't work it out. Any help would be greatly appreciated. Is it best not to have any partition at all?
    Thanks in advance.
    - Stevie

    I did some more reading and I found that Time Machine would find the older backups once a new backup is completed.  The backup ended up being a little larger than previous backups (2.65 GB vs typical incremental backups of several MB's)  but when it completed, time machine updated the last backup time/date and the oldest backup time/date properly.  So I guess, I don't have a problem.

  • Time Machine ignoring excluded items (performing full backup)

    Hi.
    I started having problems with Time Machine recently.
    My macbook hard drive has 250 GB, 80 GB free. In the Time Machine preference pane options I have selected a couple of folders so that an "estimated full backup" is 52.9 GB. When I'm running TM it tries to backup the full drive (160GB) ignoring the folders I chose to exclude.
    I have verified and repaired both my main hard drive and the external drive used for Time Machine.
    The log in the console initially says that it is going to backup 44GB and then it continues copying more data:
    1/24/10 10:14:02 PM com.apple.backupd[378] Starting standard backup
    1/24/10 10:14:03 PM com.apple.backupd[378] Backing up to: /Volumes/Time Machine Backups/Backups.backupdb
    1/24/10 10:14:10 PM com.apple.backupd[378] Backup content size: 157.0 GB excluded items size: 113.0 GB for volume Macintosh HD
    1/24/10 10:14:10 PM com.apple.backupd[378] No pre-backup thinning needed: 53.73 GB requested (including padding), 260.74 GB available
    1/24/10 11:14:04 PM com.apple.backupd[378] Copied 4.1 GB of 44.0 GB, 1471 of 782012 items
    1/25/10 12:14:05 AM com.apple.backupd[378] Copied 6.3 GB of 44.0 GB, 20599 of 782012 items
    1/25/10 1:14:06 AM com.apple.backupd[378] Copied 9.0 GB of 44.0 GB, 48709 of 782012 items
    1/25/10 2:14:06 AM com.apple.backupd[378] Copied 11.1 GB of 44.0 GB, 124469 of 782012 items
    1/25/10 3:14:07 AM com.apple.backupd[378] Copied 21.9 GB of 44.0 GB, 155468 of 782012 items
    1/25/10 4:14:08 AM com.apple.backupd[378] Copied 42.0 GB of 44.0 GB, 156348 of 782012 items
    1/25/10 5:14:08 AM com.apple.backupd[378] Copied 62.5 GB of 62.5 GB, 156455 of 782012 items
    1/25/10 6:14:09 AM com.apple.backupd[378] Copied 83.1 GB of 83.1 GB, 156517 of 782012 items
    1/25/10 7:14:10 AM com.apple.backupd[378] Copied 103.7 GB of 103.7 GB, 156648 of 782012 items
    1/25/10 7:56:21 AM com.apple.backupd[378] Copied 183712 files (114.1 GB) from volume Macintosh HD.
    1/25/10 7:56:23 AM com.apple.backupd[378] Backup canceled.
    1/25/10 7:57:55 AM com.apple.backupd[378] Stopping backupd to allow ejection of backup destination disk!
    1/25/10 8:20:53 AM [0x0-0xb50b5].backupd-helper[2308] Not starting Time Machine backup after wake - failed to resolve alias to backup volume
    1/25/10 8:46:07 AM com.apple.backupd-auto[2421] Not starting scheduled Time Machine backup - time machine destination not resolvable.
    Thanks for the help!

    Hi, and welcome to the forums.
    We have seen this on rare occasions.
    Start by Repairing your Time Machine drive and verifying your internal HD, per #A5 in the Time Machine - Troubleshooting *User Tip,* also at the top of this forum.
    Also do a "full reset" of Time Machine via #A4 there.
    If that doesn't help, there's probably something corrupted in OSX.
    You'll need to reinstall it from your Snow Leopard Install disc, then download and install the "combo" update to get back to 10.6.2. Info and download available at: http://support.apple.com/kb/DL959 Be sure to do a +Repair Permissions+ via Disk Utility (in your Applications/Utilities folder) afterwards.

  • HT3728 Time Machine only wants to do full backup not incremental

    just replaced hard drive and restored from time machine  however time machine looks like it is trying to do a full back up and  says not enough space available when should be enough for incremental. Do I delete backup and reconnect to time machine?

    There are some cases when you can continue to use the old TM backups and situations where you cannot or should not.. but before you delete your backups .. something I am always very reluctant to do, make sure you have all your files.. If you are talking about a Time Capsule you can archive off the old backup to a USB drive using 5.6 version utility or new 6.3 version. It is not available in 6.0-6.2
    Then you can safely erase the drive and start over.
    Read pondini on continuing your backups.
    B5 and B6 here.
    http://pondini.org/TM/Troubleshooting.html

  • How to set time machine to only do a full backup manually?

    I just want to do a full backup every once in a while, manually. Then turn TM back off. Can this be done? Or maybe set the frequency to just once a week/month?

    To set the frequency, Set to OFF and then place the following launchd plist in ~/Library/LaunchAgents/ (mine is saved as "com.tonyt.StartTimeMachine.plist") and then log-out and back in (or re-boot)
    This is set for weekly, Monday at 12:00am:
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
    <dict>
              <key>Label</key>
              <string>com.tonyt.StartTimeMachine</string>
              <key>ProgramArguments</key>
              <array>
                        <string>/usr/bin/tmutil</string>
                        <string>startbackup</string>
              </array>
              <key>QueueDirectories</key>
              <array/>
              <key>StartCalendarInterval</key>
              <dict>
                        <key>Hour</key>
                        <integer>0</integer>
                        <key>Minute</key>
                        <integer>0</integer>
                        <key>Weekday</key>
                        <integer>1</integer>
              </dict>
              <key>WatchPaths</key>
              <array/>
    </dict>
    </plist>
    For the 2nd of each month at 12:00am use:
    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
    <dict>
              <key>Label</key>
              <string>com.tonyt.StartTimeMachine</string>
              <key>ProgramArguments</key>
              <array>
                        <string>/usr/bin/tmutil</string>
                        <string>startbackup</string>
              </array>
              <key>QueueDirectories</key>
              <array/>
              <key>StartCalendarInterval</key>
              <dict>
                        <key>Day</key>
                        <integer>2</integer>
                        <key>Hour</key>
                        <integer>0</integer>
                        <key>Minute</key>
                        <integer>0</integer>
              </dict>
              <key>WatchPaths</key>
              <array/>
    </dict>
    </plist>

  • Time Machine - strange behavior while deleting old backups

    Not sure if this is the right place, because this is actually not on Time Capsule, but on a Time Machine on an external USB drive.
    In any case, I searched the web for "time machine delete old backups" and found many discussions of various aspects of this task. My objective is to clean up a partition on a the external drive that I no longer use for active TM backups, but to retain a small set of backups in case I need to go back to them. The partition now has other uses and I need the space. My main TM backup is now on a separate Time Capsule.
    So again my objective is not to remove all backups, but just most of them.
    It appears that the well-discussed procedure is the following:
    Go into Time Machine.
    Select the Macintosh HD.
    Go back to one of the oldest backups.
    Click on the Gear > click Delete Backup.
    This procedure will remove one Backup at a time, and it seems to take 5 - 10 minutes for each backup.
    Here is what I noticed that was "strange":
    You could delete a selected backup using the above procedure.
    For the first selected backup so deleted, there is a confirmation dialog with a warning message that it is not undoable.
    After clicking OK on the warning message, the display backs up to the "Present" backup, and the administrative password is requested.
    After the administrative password is entered, the backup starts but control is passed back to the user interface, and another backup can be selected to be deleted.
    However, after the second backup is selected and deleted, there is no warning dialog, and no request for the administrative password. At this point the user interface is busy and nothing more can be done until the backup delete is completed. Except that the Time Machine can be exited by first pressing Escape, then Cancel on the lower left of the screen.
    If the time machine is exited, there is a Delete Backups progress dialog with a progress bar for each backup  so far requested. If the second backup was requested, as in the steps above, there would be two backups.
    I discovered by playing around that either you had to wait within Time Machine for the deletion to complete, or alternatively exit Time Machine. While I was not sure what was going on, I kept starting one backup, then exiting Time Machine and re-entering Time Machine and requesting another delete operation. Each time after entering Time Machine, the warning/admin password sequence occurred and I was able to exit. And then immediately re-enter Time Machine and request another backup. Only by exiting and re-entering could another delete request be made.
    When out of Time Machine, I thus saw the Delete Backups dialog with any number of concurrent "Delete One Backup" progress bars.
    Because of the nature of the hard links used to indicate backups, I was wondering if these multiple delete operations could possibly be hung in a deadly embrace, so I decided to only do one at a time. Some further study to see if the multiple delete operations were all able to complete would be needed to know if this would be a good way to "queue up" multiple delete requests.
    Bottom line: seems like kind of an odd implementation. Would be really nice if you could select many (say 30) individual backups and delete them all at once, rather than taking 5 - 10 minutes each. Again, this is because I am trying to reclaim disk space, but not delete all the backups from a Time Machine backup set that is not in active use.
    Also, the method of "queuing up" backup delete requests is kind of odd, but seems to work, with the proviso that I have not yet confirmed that doing more than one at a time actually works.

    Heinz-G?uenter Arnold wrote:
    since the upgrade to SL it seem that Time Machine has problems to completely remove old backups completely. The "removed" backups do not show up in Time Machine anymore, but the backup folders and part of their contents can still be seen in Finder.
    Hi, and welcome to the forums.
    That happens occasionally, in both Leopard and Snow Leopard, sometimes after something was deleted from the Finder, but also after an abnormal shutdown or improper disconnection of the TM disk.
    Run a +*Repair Disk+* on it via Disk Utility, in your Applications/Utilities folder. If it finds errors, but can't fix them all, run it again (and again) until it either fixes them all, or can't fix any more.

  • Time Machine: Error occurred while creating the backup folder

    Mac Mini 2.53 GHz, 8 GB DDR3
    OS X 10.8.4
    Time Capsule 1 TB, connected via ethernet
    Airport Utility 6.3.1 (631.4)
    "Time Machine Error.  Unable to complete backup. An error occurred while creating the backup folder."
    I believe my Time Capsule is out of space and isn't removing older backups to create space for itself.  Time Machine preferences says only 98 MB available on the 1 TB volume.  I have used Pondini's superb troubleshooting page with the following results:
    A1: Time Machine Buddy Widget.  Partial log from backup attempt:
    Backing up to: /Volumes/Time Machine Backups/Backups.backupdb
    Failed to create progress log file at path:/Volumes/Time Machine Backups/Backups.backupdb/Macmini-34159E18D208 (4)/2013-04-04-223516.inProgress/.Backup.400571203.603238.log.
    Event store UUIDs don't match for volume: Macintosh HD
    Error: (Error Domain=NSCocoaErrorDomain Code=640 "You can’t save the file “598C5622-100E-456A-89AF-DEBC87A6CA89” because the volume “Time Machine Backups” is out of space." UserInfo=0x7f88a330cef0 {NSFilePath=/Volumes/Time Machine Backups/Backups.backupdb/Macmini-34159E18D208 (4)/2013-04-04-223516.inProgress/598C5622-100E-456A-89AF-DEBC87A6CA89, NSUnderlyingError=0x7f88a33056a0 "The operation couldn’t be completed. No space left on device"}) Creating directory 598C5622-100E-456A-89AF-DEBC87A6CA89
    Failed to make snapshot.
    Backup failed with error: 2
    Ejected Time Machine disk image: /Volumes/Data/Macmini-34159E18D208 (4).sparsebundle
    Ejected Time Machine network volume.
    A4: Full reset of Time Machine.  Done, did not change error from occurring on next backup attempt.
    A5b: Verify backups on Time Machine.  Done, successful (no problems).
    C10: Also attempted switching out ethernet cable and tried different ports on the Time Capsule, to no effect.
    I have no exceptions listed in Time Machine preferences (under Options) and the box for "notify when deleting old backups" is UNchecked.
    Any suggestions would be most appreciated!!

    grifftastic wrote:
    I believe my Time Capsule is out of space and isn't removing older backups to create space for itself.  Time Machine preferences says only 98 MB available on the 1 TB volume.
    "You can’t save the file “598C5622-100E-456A-89AF-DEBC87A6CA89” because the volume “Time Machine Backups” is out of space."
    Yes, it's so full it can't get started -- not even far enough to start deleting old backups.
    If you have other data there (not usually a good idea), move some of it elsewhere temporarily, and try again.
    If not, manually delete a couple of old backups, and "compact" the sparse bundle, per Time Machine - Frequently Asked Question #12.

  • Time Machine will not complete a system backup and terminates with "Unable to complete backup. An error occurred while copying files to the backup volume.  This follows a problem when Time machne terminated when the volume was almost full.

    On 11/1/2011, Time Machine (TM) terminated with an error message I did not record.  I noted that the drive was full and decided to do a separate complete bootable  system backup using Carbon Copy Clone (CCC), before clearing the TM volume and trying to start it over clean.  Part way through the full system backup CCC put up a message that there was a Physical Problem  "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16".  That was about the time that TM malfunctioned, so I assumed they were related.  After starting CCC over a couple of times, and getting the same error message, I let it go through to completion of the backup, which took three or four hours.  I then ran tests using Disk Utility and verified that there was nothing physically wrong with both the internal hard drive and the TM volume.  I also erased and reformatted the TM volume.  However, every time I started Time Machine, it would record a few GB and terminate with "Unable to complete backup. An error occurred while copying files to the backup volume".  I restarted the computer with no change in results.  Note that prior to starting the CCC backup, I "Repaired Permissions", "zapped the PRAM" and "re-set the SMC", hoping to have a clean bootable system on the backup.  I ran Techtool and no problems were found.
    I'm running this on an Intel iMac under 10.5.8 and recording to a 500GB My Passport drive.  My hard drive is only about half full at 246 GB.  My assessment is that something happened at 16-28-16 on 11/1/2001 to screwup the Backup Directory in the file at "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16". My question is, how do I fix it?
    I had just completed writing everything above here, explaining the problems I had been encountering for the past 24 hours.  I had the Time Machine window standing open on the desktop where I could see it, having recentlycleared it after the last termination.  As I was proofing what I had written, I looked at the window and noted that the clock had started a new run for a full back up, since all prior efforts had failed and the TM volume was empty.  As I watched and waited for it to fail again, as it had been doing at about 13 GB, it kept going and going until it just finished a complete backup, about 4.5 hours later, with my having done nothing.  Now my question would have to be - what could possiibly have happened to make it perform this way?   It will be interesting to see if it continue to operate normally, or if the problem will return, in a later backup run.

    jcm21 wrote:
    CCC put up a message that there was a Physical Problem  "Library/Application Support/Techtool Protection/McIntosh HD/Directory Backup 2011-11-01-16-28-16"
    You should not keep those files for long, and probably shouldn't back them up (if you need them at all -- since you do regular backups, I'm doubtful just how worthwhile that feature is).
    "Unable to complete backup. An error occurred while copying files to the backup volume".
    One of Apple's maddeningly incomplete messages. Most likely, there's a problem with a file (quite possibly the one CCC didn't like).  See #C3 in Time Machine - Troubleshooting for details and instructions on finding and fixing it.
    If you continue running the Directory Protection app, be sure to exclude your Time Machine drive from it (as it will just take up lots of room, and won't help repair your backups if there's a problem);  and exclude the folders it creates from being backed-up by Time Machine (as they'll create large backups, and you probably can't use the backed-up folders anyway), per #10 in Time Machine - Frequently Asked Questions.

  • I bought a new external hard drive for backups, but time machine won't do a full back up.  I think it is remembering backing up onto previous external hard drives, which I don't own anymore.  How do I do a new full backup?

    I bought a new external hard drive for backups, but time machine won't do a full back up. 
    I think it is remembering backing up onto previous external hard drives, which I don't own anymore.  How do I do a new full backup?
    When I bought the new (used) iMac, I also bought an external hard drive for backups.  It worked fine, but my husband stole it.
    Then I bought a new external hard drive (Seagate) and it worked fine for three weeks, then died.
    So I just got a new external hard drive, which was put together from an internal hard drive and a hard drive enclosure. 
    Time machine did the first backup today, and it should have taken 9 hours like it did on the previous first time full back up.  Instead, it took 30 minutes.  That can't be right.  I want to start over and do a full backup to make sure everything gets onto my new external hard drive, but I can't figure out how to do that.  Please help.

    Triple-click anywhere in the line below to select it:
    tmutil compare -E
    Copy the selected text to the Clipboard (command-C).
    Launch the Terminal application in any of the following ways:
    ☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
    ☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
    ☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
    Paste into the Terminal window (command-V).
    The command will take at least a few minutes to run. Eventually some lines of output will appear below what you entered.
    Each line that begins with a plus sign (“+”) represents a file that has been added to the source volume since the last snapshot was taken. These files have not been backed up yet.
    Each line that begins with an exclamation point (“!”) represents a file that has changed on the source volume. These files have been backed up, but not in their present state.
    Each line that begins with a minus sign (“-“) represents a file that has been removed from the source volume.
    At the end of the output, you’ll get some lines like the following:
    Added:
    Removed:
    Changed:
    These lines show the total amount of data added, removed, or changed on the source(s) since the last snapshot.

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