Confused about how Time Machine merges backups

Okay, I understand how TM works and that it merges many daily backups into one days worth by the next day. I've been doing some experimenting with creating a file on my desktop, backing up with TM, and then deleting it and emptying bin. I try to access this file the next day with Time Machine but it is if it never existed. Time machine shows no sign of it. It's there when I have access to the hour by hour updates. But by the next day, when everything from the previous day merged, it's gone. Am I missing the point of Time Machine? Wasn't it created for situations when you delete a file accidentally and want to bring it back sometime in the near future? What am I missing here? Thanks for your help!

mikemac22,
The last hourly backup in a given day is kept as the "daily" backup. The last daily backup in a given week is kept as the "weekly" backup, and these are kept as long as possible.
Time Machine is mainly intended to be a backup and recovery tool. Yes, if you mistakenly delete a file, it can be retrieved. However, the importance of a file is based on the length of time it remains on your "source." I doubt Apple set out to make it this way, but rather made the decision to go with this paradigm as opposed to the alternative.
You see, there is an inherent trade-off in any backup solution that works as Time Machine does. It probably would have been easy to make Time Machine "consolidate" backups, but then disk space would be consumed at a much faster rate. At some point, some decision must be made concerning the question, "when can a file be deleted from the backup?" In the case of Time Machine, as it is, a file becomes important enough to keep when it has remained on the "source" for at least one week. If it is kept for a shorter duration, and not restored, it will be deleted at some point.
On the other end of the spectrum, files that exist only in the backup will be deleted entirely when the oldest remaining backup that contains them is deleted. This "thinning" must be done in order to make room for new backups. If this action was not taken, Time Machine would just keep filling up drives, and quickly.
Time Machine is not an "archive" utility, in any sense of the term. It is not intended to maintain multiple versions of a given file for your convenience. What it is intended to do is to allow for the (almost) immediate recovery of your entire installation- user files, applications, and all- in the event you must format (erase) your source, replace your internal hard drive, or even swap computers completely. As a bonus, it will allow you to choose from several (perhaps many, depending on the size of the backup volume) backups going back in time when you do have to resort to a "Restore."
Another bonus, of course, is the ability to restore individual files that you might mistakenly delete.
Scott

Similar Messages

  • TIME MACHINE merge backup

    I'm backing up my stuff with Time Machine on an external LaCie hard disk.
    I've made 11 backup since I have it.
    Is it possible to merge all back up?
    By exemple my Itunes library is repeating in all 11 backup but with more stuff each time.
    I've erased everything on my computer but I dont I want to recreate my library but don't know where to start and I don't want to recover all my library...
    Same problem with IPhoto...
    Can somebody help me? Or do I need to do this all manually?

    Is it possible to merge all back up?
    I'm not sure what you want to do, exactly.
    Could you elaborate?
    By exemple my Itunes library is repeating in all 11 backup but with more stuff each time.
    I've erased everything on my computer but I dont I want to recreate my library but don't know where to start and I don't want to recover all my library...
    Just open Time Machine, go to /Users/your user name/Music/, click "iTunes", go to the latest backup (or the backup that has the correct library in it), and click "Restore".
    Same problem with IPhoto...
    Do the same with iPhoto.
    Just open Time Machine, navigate to /Users/your user name/Pictures, click "iPhoto Library", go to the latest backup (or the backup that has the correct library in it), and click "Restore".
    Or if you don't want those files, just restore everything else and then delete the folders I mentioned above from your internal hard drive.
    Good luck!
    P.S. Welcome to Discussions!
    Message was edited by: joshz

  • On imac 10.6.8 using current version of Aperture.  How can I access the Aperture Library  on my external hard drive that I use with time machine for backup?  I can only access the application but not the library..

    On imac 10.6.8 using current version of Aperture.  How can I access the Aperture Library  on my external hard drive that I use with time machine for backup?  I can only access the application but not the library..

    Go into Time Machine (the program not the bundle on the extrnal disk) and using Time Machine's browser go to the Folder where the library lives. You could look in the library bundle in Time Machine but that won't really tell you much,
    If you want to make sure it truely has backed up your library you will need to restore it and open the restored library with Aperture.
    If all this still has you confused you need to read up on Time Machine in order to get a feel for how it works, for what it is doing and for how to restore files from it.

  • How do I use time machine to backup to an external hard drive plugged into my airport extreme

    How do I use time machine to backup to an external hard drive plugged into my airport extreme?  I used to be able to but now time machine will not recognize my hard drive to select as a backup when plugged into my airport extreme.  I'm not sure what happened or changed.  Any help is greatly appreciated.  Thanks

    First thing to do is go to the Pondini tips page, then follow the link to his full TM site for all the details.

  • HT1175 How do I get Time Machine to backup Documents and Photos?

    My backups do not include photos and my documents folder. How can I get them included in the backup?

    Time Machine will backup everything on the Mac unless you specifically Exclude the files from being backed up. If the Documents and Photos folder are not being backed up, then someone placed them on a list of items to be Excluded from backups.
    These folders will appear in the list of Excluded items.
    Click the Time Machine "clock" icon at the top of the Mac's screen
    Click Time Machine Preferences
    Click Options
    Click on the Documents folder to highlight it, then click the - (minus) button at the bottom of the list to remove the Documents folder from Excluded items. 
    Time Machine will now back up the Documents folder on the next pass.
    Do the same for the Photo folder and it wil be backed up on the next pass as well.

  • How to save SOME time machine Mac backups from the TM disk to other disk WITHOUT formatting the destination disk?

    Hi,
    How to save SOME time machine Mac backups from the TM disk to other disk WITHOUT formatting the destination disk?
    I have a Time Machine disk (A) including the backups of several different Macs (B, C, D & E) generated with an old Mac OS X 10.5.8 (iMac PowerPC) over the years.
    I have transferred the old Mac contents to a new Mac with OS X 10.8.3 using Migration Assitant. All OK.
    Now, I want to erase such TM disk A to use if for other purposes, but first, I would like to RECOVER the backups of some Macs inside it (D and E). Is that possible WITHOUT formatting the destination disk and selecting only some Macs from the TM disk and not the fulll TM disk? How?
    Thanks.

    Thanks for the reply. I do not think that is messy, anway. I simply used the same external disk as Time Machine disk for different Macs. And that worked OK all the time for years.
    The ExternalTimeMachineDisk contains the folder Backups.backupdb
    which contains the following folders (each one corresponding to the Time Machine backup made from each Mac):
    Mac1
    Mac2
    MacBook1
    MacBook2
    In relation to my message above, is it possible to select specific files, folders or full Mac backups from such Time Machine disk and save them to other disk? How?
    Thanks.

  • How do I upgrade to snow leopard and then restore my files from my time machine HDD backup...without losing any data or reinstalling leopard (10.5)?

    How do I upgrade to snow leopard (from leopard 10.5) and then restore my files from my time machine HDD backup...without losing any data or reinstalling leopard (10.5)?

    Hello, it's great you have a backup, but 10.6 should just Install 10.6 system files over the top of 10.5 system files, & leave all your data intact on the drive.

  • How to use Time Machine to backup a disk image

    I have my iPhoto libray in a disk image in the shared folder so that it can be shared by two user accounts.  Is there a way to use Time Machine to backup the mounted image?  I don't want to backup the entire disk image file every time there is a change in iPhoto (over 200GB!).  I'd like to just backup the changes, but so far, it doesn't seem to work?

    There is no way to back up a mounted, writable disk image with Time Machine. If you want to keep data on a disk image, the best option is to convert it to a sparsebundle, which consists of many small files instead of one big file. It will be backed up much more efficiently, but only when not mounted.

  • Can I set Time Machine to backup both my hard drive and an external hard drive?

    Hi. I've been working with a lot of family video lately and my internal hard drive has filled up significantly. iMovie doesn't seem to have a good archiving facility like Adobe InDesign which I use at work were all the relevant files are gathered together into one folder. Apple advised me to relocate my movie files to an external hard drive and herein lies my query.
    Is there a way for me to set Time Machine to backup both my iMac's internal drive and the external hard drive that would contain my movie files? I've been using Time Machine for my backups for a few years now, but backing up the external as well has me stumped. If Time Machine could be used then all the necessary file accociations etc would be safely backed up as well - that's why I don't want to have to manually backup the external.
    Anyone have any ideas? Thanks!

    7string48 wrote:
    Thanks so much Pondini!!  You just quickly answered a question that none of the Mac people in 3 stores or Apple Care have been able to answer.If you can format it HFS+ (any variation of Mac OS Extended), it will work.  If not, it won't.  
    I'm not too surprised about the Apple Stores, as they don't get much training on Time Machine.  But AppleCare sure ought to know. 
    Oh...what about if the external drive is an array...like a Drobo with it's own proprietary formatting...I guess that would not work...??
    I've never used a Drobo.  A number of folks here have used them as their Time Machine drives, but I don't recall seeing anyone try to back one up with TM, so can't say for sure.  But if you can format it as HFS+ (any variation of Mac OS Extended), it will work.  If not, it won't.
    At least part of the reason is, Time Machine uses the File System Event Store, a hidden log of changes that OSX keeps on each Mac-formatted disk/partition, to figure out what's changed and needs to be backed-up.  See How Time Machine works its Magic for details.
    See Time Machine - Frequently Asked Question #32 for details and considerations of backing-up multiple volumes with Time Machine.
    However, even if it will work, that may not be your best strategy, depending on your circumstances:
    Since Time Machine keeps copies of things you've changed or deleted, the destination needs to be considerably larger than the data being backed-up.  How much larger varies widely depending on how you use your Mac, but a general "rule of thumb" is, it needs at least twice the space to be able to keep a reasonable "depth" of backups for you.
    If you have a large internal HD, fairly full, plus a large external HD, and the files on the external don't change frequently, you might want to use Time Machine for the internal, and a different app to a different disk or partition, on a different schedule, for the external.  Especially if space is a consideration, you might not need to keep previous versions of files on the externals.  See Time Machine - Frequently Asked Question #27 for some alternatives.

  • Time machine and backup

    I have a quick question.  I'm pretty new to macbooks.  I just recently bought a macbook pro 13" and hooked it up to an external harddrive.  I used Time Machine to backup the entire system.  I take a lot of pictures so I've used up about half my hard drive capacity.  My question is....can I use the same external hard drive just to store pics and also as Time Machine?  Or...do I have to buy another external hard drive to just store pics?

    Time Machine works best if it has its own, exclusive space.  If you want to put other things on the same drive, partition it.  See #3 in Time Machine - Frequently Asked Questions.
    But before you do that, how are you going to back up those pictures?  If they're in the same partition as your backups, Time Machine cannot back them up.  If they're in a separate partition of the same drive, when you tell Time Machine to back it up, it will send you a message reminding you that it's not a good idea to have your originals and backups on the same physical HD.  When (not if) it fails, you risk losing both copies.
    If your pictures are valuable, yes, get another drive for them.  Format it for a Mac, per #1 in Formatting, Partitioning, Verifying, and Repairing Disks.  External HDs are excluded from Time Machine by default, so go to Time Machine prefs > Options, select the new drive, and click the minus sign at the bottom to remove it from the exclusions box.  Then Time Machine will back it up along with your internal HD.

  • Time machine fails backup

    Can anyone advise me?
    I use Time Machine to backup. All has been well the backups were flawless until recently when I decided that I needed to encrypt my sensitive work and personal files placing them into an encrypted Apple Disk Image on my hard disk. Ever since then at some stage Time Machine had decided that there is insufficient disk space and the backup fails.
    When it first began to fail I increased the backup disk space and began a fresh start backup.
    The backup disk is now 1 TB and the total amount on my hard disk to be backed up to backup is 183 gb which includes the disk image which is 40 gb.
    The only change has been the creation of the disk image otherwise everything else is the same. Would it be better to have a number of disk image files and spread the encrypted material across smaller dmgs?

    Thank you for your response which is very helpful. I have changed the dmg to a sparse bundle and Time Machine appears to be handling the backup better.
    Initially I was confused about the difference between a sparse image and a sparse bundle but read in https://discussions.apple.com/thread/2001162?start=0&tstart=0 what the difference is and see that the sparse bundle appears to have been developed by Apple for exactly my kind of problem.
    You say that "… be aware that disk image files are not backed up at all while the image is mounted."
    I do not wish to disagree but when I was backing up the vanilla dmg and also last night backing the sparse bundle dmg the back up has worked and did work on the mounted disk. In my case the disc is always mounted as it contains the bulk of the files I work on. Perhaps I have misunderstood what you were saying.
    Thank you again for your response.

  • Time machine email backup showing incorrect emails

    I have been using time machine to backup my emails. The great thing about time machine is that I could always go back in time and restore yesterdays emails after I had just deleted them by accident. Since I upgraded to Yosemite I notice that in time machine my yesterdays inbox not only contains yesterdays emails, but many more emails that I have moved or deleted already. My mailboxes are imap mailboxes, but all emails are also stored on my macbook air. Does anyone know how to get the old behaviour back, as before Yosemite? Or is this a confirmed bug? Any info will be much appreciated.

    Inside the V2 folder are subfolders representing your Mail accounts. The names refer to the email addresses you use.
    From the Mail menu bar, select
    File ▹ Import Mailboxes...
    Import from the mailboxes in the restored folder. The imported messages will appear in a new mailbox. Move the ones you want to keep wherever you like and delete the rest.

  • Time Machine nuking backups, starting from scratch!

    ok, i just received this warning:
    and now i't doing a backup that is slated to take more than "several hours."
    is this common? how often can i expect this?

    Hello,
    Should you click “Start New Backup”? Not yet! If you see the dialog above, your existing Time Machine backup is corrupt, and you might not be able to recover data from it. But you can save a copy of the corrupt bundle and, perhaps, extract some data from it if needed.
    Ask yourself if Time Machine has saved data you might need before deciding what to do next:
    If you are sure you won’t need anything backed up before today, click “Start New Backup” and let Time Machine do its thing.
    Otherwise, click “Back Up Later” and save a copy before letting Time Machine start a new backup. Just look for a file called “computername.sparsebundle” (for network backups) or “Backups.backupdb” (for local ones) and create a copy with a different name. You can open sparsebundle files with DiskImageMounter and browse them like any other disk. More information is available here.
    There you go. If you click “Start New Backup” when you see this dialog box, Time Machine will erase all of your old backup data and start a new bundle. It won’t be corrupt, but it will be empty.
    Note that you can manually initiate a Time Machine backup integrity check by option-clicking the “Time Machine” icon in the menu bar and selecting “Verify Backups.”
    http://blog.fosketts.net/2010/08/11/time-machine-completed-verification-backups- improve-reliability-time-machine-create-backup/
    According to This Time Machine resource   “This appears only on Snow Leopard, and started with the Time Capsule Backup Update 1.0 in mid-May of 2010.  It also seems to have been included in the 10.6.3 v1.1 update and 10.6.4.”
    So, what can you do about it?  Grin and bear it, it seems, until Apple fixes it.
    One thing you can do to make the backup take less time is to connect your machine to your Time Capsule or other backup drive via Ethernet for the duration of the initial backup.
    http://www.theinternetpatrol.com/the-dreaded-time-machine-has-completed-a-verifi cation-of-your-backups-to-improve-reliability-time-machine-must-create-a-new-bac kup-for-you-message-and-why-you-are-seeing-it/
    Time Machine: About "Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you."...
    http://support.apple.com/kb/HT4076

  • HT3275 time machine wireless backup

    We have a network admin with 5 Mac Air Books that connect to an Aruba wireless network most of the time.  When they are connected via wireless, their time machine backups fail.  If they connect wired, it is successful.   I am coming into this issue completely cold.  I'm not even a MAC guy.. (that is to change very soon   )  .
    Any suggestions?  What to look for?   Does the agent point to the physical NIC and not the wireless ??
    Thanks in advance,
    Dan

    It sounds like you are about to start either a massive sale of MBA.. or a Damascus Road conversion experience!!
    The TM connects by AFP protocol.. (another new part of your learning curve.. yeap, apple have their very own protocol)... to the TC... which should be in bridge.
    What appears to be happening is the Lion OS is having some issues remembering where the TC is.. even though internet is still working. This failure happens in pure Apple environment so I doubt your Aruba wireless is related at all. Generally it happens on both wired and wireless.. so your issue is a little different in only failing via wireless. Open a terminal (under applications, utilities, and use the arp -a command to see if the TC MAC address is lost)
    There is some great info for you to read.
    http://pondini.org/TM/Troubleshooting.html
    Installing the widget.. allows easier access to the logs which give fairly detailed picture of what has failed.. look at A1.
    But I also recommend you read even if hastily survey the FAQ on the site and a bit of explanation of how Time Machine actually works and it own quirks.
    The Log in the TC is also helpful.. I am assuming the MBA are all on Lion.. so make sure you download airport utility 5.6 for Lion as the installed version 6.0 is the latest but not so greatest version lacking the depth of the original v5 utility.
    If you find a series of AFP connect and disconnect in the log.. this is a bug in Lion/7.6 firmware..
    You might do better going back to 7.5.2 in the TC which was much more stable.
    Good luck.

  • Time Machine everytime backups everyting!

    My main system disk "Macintosh HD", 500 GB
    Media disk is exernal disk named "Media", 1000 GB.
    My Time Machine disk is named "DeLorean" and its external 1,500 GB.
    I have about 340 GB more free space in the Time Machine disk than my data currently uses up.
    My problem is that the Time Machine VERY often starts its backup FROM THE SCRATCH!
    Doing FULL BACKUP! Deleting over 800 GB of data. If you see my logs, you will see it doesnt like something about the external "Media" disk.
    It does this thing called "Deep event scan at path:/Volumes/Media reason:must scan subdirs|"... * see logs later.
    Funny thing is, if i delete/erase the backup, or let it do the FULL backup when it wants, it usually after that does the normal smaller backup just fine.
    BUT if I unmount the Media disk even once and do one incremental backup(which it does fine), then after i mount the Media back, next time it does this FULL backup and says in the logs about the Deep even scan.
    All my disks are encrypted via FileVault2. Shouldnt time machine still work or is this setup fine?
    Here are the logs. Yesterday i even shuffled all my disks and erased the Media and the time machine disk and encrypted them again.
    You can see the first full backup starting at 2 am, then ONE succesfull incremental backup while both disk were still mounted. When i woke up at (13:20 pm) I did one incremental backup without the Media (ummounted it) and then again new one with media mounted (13:29 pm) and BAM ! It started FULL backup (deleting 800+ GB of data). Nothing has been changed on the media disk during that time. Weird !
    Logs showing fresh first new backup stuff:
    Dec 18 01:03:48 imac com.apple.backupd[95130]: Copied 81.9 GB of 1047.6 GB, 1469 of 1156879 items
    Dec 18 02:03:49 imac com.apple.backupd[95130]: Copied 172.8 GB of 1047.6 GB, 1516 of 1156879 items
    Dec 18 03:03:50 imac com.apple.backupd[95130]: Copied 264.8 GB of 1047.6 GB, 1563 of 1156879 items
    Dec 18 04:03:50 imac com.apple.backupd[95130]: Copied 357.1 GB of 1047.6 GB, 1615 of 1156879 items
    Dec 18 05:03:51 imac com.apple.backupd[95130]: Copied 449.1 GB of 1047.6 GB, 1666 of 1156879 items
    Dec 18 06:03:51 imac com.apple.backupd[95130]: Copied 541.5 GB of 1047.6 GB, 1696 of 1156879 items
    Dec 18 07:03:52 imac com.apple.backupd[95130]: Copied 633.6 GB of 1047.6 GB, 1741 of 1156879 items
    Dec 18 08:03:52 imac com.apple.backupd[95130]: Copied 725.6 GB of 1047.6 GB, 1786 of 1156879 items
    Dec 18 08:10:55 imac com.apple.backupd[95130]: Copied 1796 files (736.3 GB) from volume Media.
    Dec 18 09:03:53 imac com.apple.backupd[95130]: Copied 773.9 GB of 1047.6 GB, 621723 of 1156879 items
    Dec 18 10:03:54 imac com.apple.backupd[95130]: Copied 803.6 GB of 1047.6 GB, 936589 of 1156879 items
    Dec 18 11:03:54 imac com.apple.backupd[95130]: Copied 878.4 GB of 1047.6 GB, 1019840 of 1156879 items
    Dec 18 12:03:54 imac com.apple.backupd[95130]: Copied 951.6 GB of 1047.6 GB, 1107382 of 1156879 items
    Dec 18 13:03:54 imac com.apple.backupd[95130]: Copied 1034.6 GB of 1047.6 GB, 1110125 of 1156879 items
    Dec 18 13:13:49 imac com.apple.backupd[95130]: Copied 1140722 files (1041.4 GB) from volume Macintosh HD.
    Dec 18 13:13:58 imac com.apple.backupd[95130]: 1.72 GB required (including padding), 341.53 GB available
    Dec 18 13:13:58 imac com.apple.backupd[95130]: Copied 6 files (0 bytes) from volume Media.
    Dec 18 13:14:15 imac com.apple.backupd[95130]: Copied 6665 files (1.7 MB) from volume Macintosh HD.
    Dec 18 13:14:17 imac com.apple.backupd[95130]: Copying Lion Recovery set
    Dec 18 13:14:42 imac com.apple.backupd[95130]: Backed up Lion Recovery to /Volumes/DeLorean/Backups.backupdb
    Dec 18 13:14:45 imac com.apple.backupd[95130]: Starting post-backup thinning
    Dec 18 13:14:45 imac com.apple.backupd[95130]: No post-back up thinning needed: no expired backups exist
    Dec 18 13:14:45 imac com.apple.backupd[95130]: Backup completed successfully.
    Ends.
    This backup i Initiated after i woke up, with both system disk and external "media" mounted:
    Dec 18 13:22:02 imac com.apple.backupd[5781]: Starting standard backup
    Dec 18 13:22:02 imac com.apple.backupd[5781]: Backing up to: /Volumes/DeLorean/Backups.backupdb
    Dec 18 13:22:05 imac com.apple.backupd[5781]: 1.70 GB required (including padding), 340.96 GB available
    Dec 18 13:22:05 imac com.apple.backupd[5781]: Waiting for index to be ready (100)
    Dec 18 13:23:05 imac com.apple.backupd[5781]: Waiting for index to be ready (100)
    Dec 18 13:23:48 imac com.apple.backupd[5781]: Copied 6 files (0 bytes) from volume Media.
    Dec 18 13:23:55 imac com.apple.backupd[5781]: Copied 1780 files (8.6 MB) from volume Macintosh HD.
    Dec 18 13:23:56 imac com.apple.backupd[5781]: 1.37 GB required (including padding), 341.39 GB available
    Dec 18 13:23:56 imac com.apple.backupd[5781]: Copied 6 files (0 bytes) from volume Media.
    Dec 18 13:23:59 imac com.apple.backupd[5781]: Copied 1596 files (268 bytes) from volume Macintosh HD.
    Dec 18 13:24:00 imac com.apple.backupd[5781]: Starting post-backup thinning
    Dec 18 13:24:00 imac com.apple.backupd[5781]: No post-back up thinning needed: no expired backups exist
    Dec 18 13:24:00 imac com.apple.backupd[5781]: Backup completed successfully.
    Ends.. This seems to work like it should.
    Now, see the time stamps, i just toke some coffee and came back....
    This next backup is done while "Media" drive has been umounted:
    Dec 18 13:28:00 imac com.apple.backupd[5962]: Starting standard backup
    Dec 18 13:28:00 imac com.apple.backupd[5962]: Backing up to: /Volumes/DeLorean/Backups.backupdb
    Dec 18 13:28:01 imac com.apple.backupd[5962]: 1.37 GB required (including padding), 341.39 GB available
    Dec 18 13:28:04 imac com.apple.backupd[5962]: Copied 1455 files (78 KB) from volume Macintosh HD.
    Dec 18 13:28:04 imac com.apple.backupd[5962]: 1.37 GB required (including padding), 341.39 GB available
    Dec 18 13:28:05 imac com.apple.backupd[5962]: Copied 115 files (93 bytes) from volume Macintosh HD.
    Dec 18 13:28:05 imac com.apple.backupd[5962]: Starting post-backup thinning
    Dec 18 13:28:05 imac com.apple.backupd[5962]: No post-back up thinning needed: no expired backups exist
    Dec 18 13:28:05 imac com.apple.backupd[5962]: Backup completed successfully.
    Incremental backup seems to finnish ok, without the "Media" drive.
    This backup is the third one done just after couple minutes after i mounted the "Media" drive back on:
    Dec 18 13:31:49 imac com.apple.backupd[6025]: Starting standard backup
    Dec 18 13:31:49 imac com.apple.backupd[6025]: Backing up to: /Volumes/DeLorean/Backups.backupdb
    Dec 18 13:31:49 imac com.apple.backupd[6025]: Deep event scan at path:/Volumes/Media reason:must scan subdirs|
    Dec 18 13:31:49 imac com.apple.backupd[6025]: Finished scan
    Dec 18 13:31:51 imac com.apple.backupd[6025]: 884.92 GB required (including padding), 341.39 GB available
    Dec 18 13:31:51 imac com.apple.backupd[6025]: No expired backups exist - deleting oldest backups to make room
    Dec 18 13:31:52 imac com.apple.backupd[6025]: Deleted backup /Volumes/DeLorean/Backups.backupdb/imac/2011-12-18-131415 containing 8.7 MB; 341.40 GB now available, 884.92 GB required
    Dec 18 13:31:52 imac com.apple.backupd[6025]: Removed 1 expired backups so far, more space is needed - deleting oldest backups to make room
    Dec 18 13:32:02 imac com.apple.backupd[6025]: Deleted backup /Volumes/DeLorean/Backups.backupdb/imac/2011-12-18-132359 containing 736.30 GB; 1.05 TB now available, 884.92 GB required
    Dec 18 13:32:02 imac com.apple.backupd[6025]: Deleted 2 backups containing 736.31 GB total; 1.05 TB now available, 884.92 GB required
    Dec 18 13:32:02 imac com.apple.backupd[6025]: Backup date range was shortened: oldest backup is now Dec 18, 2011
    Dec 18 13:35:02 imac com.apple.backupd[6025]: Copied 526 files (4.3 GB) from volume Media.
    Dec 18 13:35:03 imac com.apple.backupd[6025]: Backup canceled.
    I canceled that scan(it would take about 12 hours again
    OK. Couple questions:
    - Why time machine does this deep scan? What does it actually mean?
    - Why time machine thinks that it needs to do a 800GB worth of new backup. Those data have not changed a bit (they are movies).
    - How its related to the unmount/mounting the Media drive?
    I would really hope some answers from somebody. I have strugled with this issue almost a month now.
    Thanks!

    ECONOMAN wrote:
    Time Machine Incremental Backups S...L...O...W and seem to bog down things so as to make the machine unusable. Why doesn't it simply backup changes, not the entire drive (less exclusions)?
    Normally, that's exactly what it does. So start by calming down.
    And, it gobbles processing power so I can't even check mail.
    Can you schedule the frigging thing or do I just stop it all the time in order to get anything done?
    It's cute, but kind of worthless.
    First, are these backups larger than you think they ought to be? If so, that's likely at least part of your problem. See #D4 of the Time Machine - Troubleshooting *User Tip,* also at the top of this forum, for some possible causes and a way to find out just what's going on.
    If that's no help, or they're still slow, try all the things in #D2 of the Troubleshooting Tip.
    If that doesn't help, post back with details, including all the messages, your setup (especially the destination for the backups), what you've done, and the results.

Maybe you are looking for