7 Replies Latest reply: Apr 1, 2012 8:24 PM by Gator79
mfreckle Level 1 Level 1 (0 points)
I've had time machine running for a long time now. It worked flawlessly for quite some time.

Today it gave me the error that there was not enough free space on the disk to complete the backup (the error message says something like there is 360 GB of data on the Time Machine drive already, 140 GB of free space and it would require more than that to complete my backup). I have a 500 GB Time Machine disk and my Mac has a 500 GB hard drive, so I should technically never run out of space.

The Time Machine almost acts like this is the first time I've ever backed up, which is not true. Shouldn't Time Machine delete old backups to make space for the new? What's even weirder is that if I open the "Star Wars" window of Time Machine I only see one backup from March 31, 2011, but I have been running Time Machine for well over a year now. I'm totally confused as to what happened. Any advice on how to get my Time Machine back up and running (without buying a new drive) would help!

iMac, MacBook Pro, Mac Mini, iPad, iPhone, Mac OS X (10.6.7)
  • 1. Re: Doesn't Time Machine delete old backups when it needs more space?
    Kappy Level 10 Level 10 (226,795 points)
    About TM "Backup Drive is Full" Alert

    TM only deletes older files if they have been deleted from the source and when TM needs space on the backup drive for a new incremental backup. Time Machine "thins" it's backups; hourly backups over 24 hours old, except the first of the day; those "daily" backups over 30 days old, except the first of the week. The weeklies are kept as long as there's room.

    So, how long a backup file remains depends on how long it was on your Mac before being deleted, assuming you do at least one backup per day. If it was there for at least 24 hours, it will be kept for at least a month. If it was there for at least a week, it will be kept as long as there's room.

    Note, that on a Time Capsule the sparsebundle grows in size as needed, but doesn't shrink. Thus, from the user's view of the TC it appears that no space has been freed, although there may be space in the sparsebundle.

    Once TM has found it cannot free up enough space for a new backup it reports the disk is full. You can either erase the backup drive and start your backups anew or replace the drive with a larger drive.

    Actually, a TM backup drive needs to be at least twice the capacity of the drive it backs up.
  • 2. Re: Doesn't Time Machine delete old backups when it needs more space?
    mberardinelli Level 1 Level 1 (30 points)
    Not true. I have a 500GB internal drive and a 500GB Time Machine drive, and I never have problems. Mainly because my entire 500GB internal is not totally filled.

    Time Machine should automatically delete older backups when it runs out of space, yes.

    You may have to go into Time Machine and manually delete some of your older backups to free some space.
  • 3. Re: Doesn't Time Machine delete old backups when it needs more space?
    mfreckle Level 1 Level 1 (0 points)
    Thanks mberardinelli for your reply. I do not think that the problem Kappy was describing is my problem. I know that the entire drive on my Mac is not full and that to really need twice the capacity of my drive it sounds like I would need to be changing my files often (which I don't). I also use windows set up in a boot camp partition that has at least 100GB of my hard drive, so all of my hard drive space is not available for a TM backup.

    What concerns me is that I have been using TM for so long and right now all I can find is a back up from March 31st. The rest of the windows in the "Star Wars" Time Machine interface are blank. When I open my Time Machine drive in Finder all I see is a folder for March 31, 2011. I haven't checked my Time Machine in a long time, but I am assuming that I should see folders for as many days as the back up drive can hold.

    Should I use disk utility to erase the drive and start over? I am hesitant to do that, but I really think there is an error in the system at this point and I need to start fresh.
  • 4. Re: Doesn't Time Machine delete old backups when it needs more space?
    mberardinelli Level 1 Level 1 (30 points)
    Hmm, that sounds like you may have had some kind of an error with your Time Machine drive and perhaps your old backups have become corrupted. If you open Disk Utility, try doing a Verify Disk with your Time Machine drive selected. If it turns out that the disk had errors, Disk Utility may be able to fix them. The other thing you can try is a permission repair, but that may not do you any good.

    It sounds more like the problem is with the Time Machine drive and not with your internal bootable drive, since you didn't receive any error messages relating to corrupted system files or anything of that sort.

    You can check the Console logs to see if any "silent" errors occurred while running that backup on March 31st and post them here as well.
  • 5. Re: Doesn't Time Machine delete old backups when it needs more space?
    lysander-spooner Level 1 Level 1 (20 points)
    You see only one backup in the Time Machine window because Time Machine has deleted the older backups to make space to do the current backup.

    Time machine needs some working space to do its backups, and so backing up a 500GB drive onto a 500GB time machine volume is not ideal.

    However, I do essentially the same thing, and what I do, when I have this problem, is exclude things from the backup.

    First off, figure out what you changed. If you moved things from one partition to another, then that will cause a backup of the size of the thing that was moved. This may be why you have a large backup.

    When I have this problem, I exclude large things that have changed recently from the backup. This makes the backup smaller, and means that there is less working space needed. I do this until I get a successful backup. Then I remove things, one by one, from the exclusion list, and back up after each one.

    So, for instance if you just put 4 new folders on your drive, each of which s 20GB of data and they are named A, B, C and D, add all four to the exclusion list, do a backup, then remove A from the exclusion list (leaving B, C & D on it) and do a backup, and continue like this, adding 20GB of backup data each time until none of the new data is on the exclusion list and you get a completed backup.


    Another possible issue, if you use multiple partitions, is that Time Machine may be keeping an obsolete backup of a partition that you previously reformatted. To see if this is the case, go into time machine (The universe interface) and go back to the most recent backup it shows. Click on your computer and see what partitions show up-- are any of them old ones that have been reformatted and renamed? You may be storing a duplicate backup because Time Machine does not realize that the disk that went away isn't coming back (because it has been reformatted as a different partition)

    You can right-click on these items and remove them from your backup by sleecting "Delete all backups of...." This will free up space as well.
  • 6. Re: Doesn't Time Machine delete old backups when it needs more space?
    Cerver Level 1 Level 1 (0 points)

    i wish this were true in my case. i have went into the time machine area, went into a specific back up, removed about 15 movies that were at least 10GB of space and choose to remove all backups of this file. i then entered in my password and heard the trash sound. i then closed time machine and was back at my desktop where my 3TB TM backup drive did not change the file size at all. It did not save me any space and im wondering how i can remove old backup files to save more room on my TM drive and get rid of those files that i no longer wish to have backup'd.




  • 7. Re: Doesn't Time Machine delete old backups when it needs more space?
    Gator79 Level 1 Level 1 (0 points)

    I hate the Time Machine! Mine has never worked correctly.  I only need it to back up my large photo portfolio, video files, and music.  The device will not let me delete the old backup to make room for the new complete backup.  Without getting rid of the old backup I can complete the new backup.  I thought that buying the Apple product would make things easy.  I should have just bought a Western Digital External Hard Drive!