Time Machine claims not enough space, but there's plenty

The problem is often, or perhaps always, caused by backing up a volume on a drive that doesn't have a GUID or CoreStorage partition table. Time Machine doesn't work reliably with other partition types.

To confirm, launch Disk Utility and select the icon of the drive in question—not any of the volume icons nested below it. At the bottom of the window, note the Type. If it's not GUID Partition Scheme or Logical Volume Group, see below.

This procedure will destroy all data on the drive. Afterwards, restore from a backup. To be safe, you must have at least two complete, independent, up-to-date backups. One is not enough.

Select the Partition tab. From the Partition Layout menu in the window, select

One Partition

From the Format menu, select

Mac OS Extended (Journaled)

Click the Options button and select

GUID Partition Table

in the sheet that appears.

Click the Apply button and confirm when prompted.

The next time you back up, you may be prompted to "inherit" the backup history. Confirm. Even so, TM may copy all or almost all the files. After that, only the files that have changed should be copied.

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.

Time Machine sees the upgrade to Yosemite as a "new" computer, so it wants to make a new, full backup separate from the other backup. Hence, there isn't sufficient space on the drive even after trimming old files. You have these options: a. erase the backup drive and start over; b. get another backup drive to use.

A third-party NAS is unsuitable for use with Time Machine, especially if it's your only backup. I know this isn't the answer you want. I know Time Machine accepts the NAS as a backup destination. I know that the manufacturer says the device will work with Time Machine, and I also know that it usually seems to work. Except when you try to restore, and find that you can't.

Apple has published a specification for network devices that work with Time Machine. None of the third-party NAS vendors, as far as I know, meets that specification. They all use the incomplete, obsolete Netatalk implementation of Apple Filing Protocol.

If you want network backup, use as the destination either an Apple Time Capsule or an external storage device connected to another Mac or to an 802.11ac AirPort base station. Only the 802.11ac base stations support Time Machine, not any older model.

Otherwise, don't use Time Machine at all. There are other ways to back up, though none of them is anywhere near as efficient or as well integrated with OS X. I don't have a specific recommendation.

If you're determined to keep using the NAS with Time Machine, your only recourse for any problems that result is to the manufacturer (which will blame Apple, or you, or anyone but itself.)

I have the exact same problem with almost the same setup: MacBook Pro (Retina, 13-inch, Late 2012) running Yosemite 10.10, an external harddrive and a Time Capsule 2 TB (4th Generation, Version 7.6.4). I even took the same actions as geoff2 (deleting the complete set of backups from Mavericks and making a new complete backup on Yosemite). On my internal harddrive 270 GB are occupied, on my external harddrive around 980 GB are occupied and the MacBook of my girlfriend is also backed up to the Time Capsule. At the moment around 646 GB are available on the Time Capsule.

Now I get the same error message saying, that 977 GB are needed for a backup but only 650 GB are available. Interestingly backups without the external drive connected will complete without any problems.

The external drive has a "GUID Partition Table". So it seems both of Linc Davis suggestions don't apply to the problem (we both have either GUID Partition Table or Logical Volume Group and the issue appears both on a NAS-Storage and on a Time Capsule).

Looking for additional information I looked into the console and found the following report: "Inheritance scan may be required for '/Volumes/Dolphin', associated with previous UUID: BA36E38E-71F9-39E1-BF72-36AF9D4BB45F". "Dolphin" is the name of the external drive. What does that mean? Is it of any relevance? For more information I will post all the reports concerning the backup below (it's mainly about trying to free more space on the TC by deleting old backups). "Yosemite" is my internal OS X Volume, "Hamster" is the name of the Volume on the TC, "Nifty" is a Nifty mini drive in the SD-Card-Slot.

I already verified the backups using the Option-Click on the menu bar symbol and I deleted and rebuilt the Spotlight index but it changed nothing. We could of course delete the backup volume (NAS or TC) and start a new backup, but I have a feeling, that the issue will appear again afterwards. Any other suggestions?

08.11.14 16:46:06,033 com.apple.backupd[4227]: Starting manual backup

08.11.14 16:46:06,071 com.apple.backupd[4227]: Network destination already mounted at: /Volumes/Hamster

08.11.14 16:46:11,000 kernel[0]: hfs: mounted Time Machine-Backups on device disk6s2

08.11.14 16:46:13,146 com.apple.backupd[4227]: Disk image /Volumes/Hamster/Nikos MacBook Pro 13" (2).sparsebundle mounted at: /Volumes/Time Machine-Backups

08.11.14 16:46:14,908 com.apple.backupd[4227]: Backing up to /dev/disk6s2: /Volumes/Time Machine-Backups/Backups.backupdb

08.11.14 16:46:19,914 com.apple.backupd[4227]: Inheritance scan may be required for '/Volumes/Dolphin', associated with previous UUID: BA36E38E-71F9-39E1-BF72-36AF9D4BB45F

08.11.14 16:46:27,375 com.apple.backupd[4227]: Will copy (10 MB) from Yosemite

08.11.14 16:46:32,745 com.apple.backupd[4227]: Will copy (0 KB) from Dolphin

08.11.14 16:46:32,748 com.apple.backupd[4227]: Will copy (0 KB) from Nifty

08.11.14 16:46:32,749 com.apple.backupd[4227]: Found 137158 files (954.27 GB) needing backup

08.11.14 16:46:32,752 com.apple.backupd[4227]: 977.06 GB required (including padding), 646.65 GB available

08.11.14 16:46:32,765 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-08-164619.inProgress/B65EE357-083D-4E0B-900B-42910289B9C4 containing 4 KB; 646.65 GB now available, 977.06 GB required

08.11.14 16:46:32,767 com.apple.backupd[4227]: Removed 1 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:49:20,472 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-07-111400 containing 627.9 MB; 647.28 GB now available, 977.06 GB required

08.11.14 16:49:20,472 com.apple.backupd[4227]: Removed 2 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:50:12,817 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-07-171215 containing 59.4 MB; 647.34 GB now available, 977.06 GB required

08.11.14 16:50:12,818 com.apple.backupd[4227]: Removed 3 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:50:48,156 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-07-183323 containing 42.4 MB; 647.38 GB now available, 977.06 GB required

08.11.14 16:50:48,156 com.apple.backupd[4227]: Removed 4 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:51:07,147 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-08-112446 containing 25.3 MB; 647.41 GB now available, 977.06 GB required

08.11.14 16:51:07,147 com.apple.backupd[4227]: Removed 5 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:51:28,134 com.apple.backupd[4227]: Deleted backup /Volumes/Time Machine-Backups/Backups.backupdb/Nikos MacBook Pro 13" (2)/2014-11-08-132002 containing 11.5 MB; 647.42 GB now available, 977.06 GB required

08.11.14 16:51:28,134 com.apple.backupd[4227]: Removed 6 expired backups so far, more space is needed - deleting oldest backups to make room

08.11.14 16:51:28,135 com.apple.backupd[4227]: Deleted 6 backups containing 766.6 MB total; 647.42 GB now available, 977.06 GB required

08.11.14 16:51:28,136 com.apple.backupd[4227]: Backup date range was shortened: oldest backup is now Nov 8, 2014

08.11.14 16:51:29,353 com.apple.backupd[4227]: Backup failed with error 7: Not enough available disk space on the target volume.

08.11.14 16:51:36,000 kernel[0]: hfs: unmount initiated on Time Machine-Backups on device disk6s2

08.11.14 16:51:37,508 com.apple.backupd[4227]: Ejected Time Machine disk image: /Volumes/Hamster/Nikos MacBook Pro 13" (2).sparsebundle

08.11.14 16:51:38,227 com.apple.backupd[4227]: Ejected Time Machine network volume.

08.11.14 16:53:43,804 SystemUIServer[431]: Attempt to use XPC with a MachService that has HideUntilCheckIn set. This will result in unpredictable behavior: com.apple.backupd.status.xpc

08.11.14 16:53:43,806 com.apple.prefs.backup.remoteservice[529]: Attempt to use XPC with a MachService that has HideUntilCheckIn set. This will result in unpredictable behavior: com.apple.backupd.status.xpc

I have exactly the same problem as geoff2and niqu

I tried formating the Time Machine drive and starting from scratch. It initially worked fine and then I started getting messages saying there was not enough space. I am also using Yosemite. I am also backing up my iMac's internal drive plus one external drive. The TIme Machine drive is heaps bigger than the other two drives added together. Should be lots of space.

jody

same problem here.

I also tried formating the BackUp Drive. It worked for a few days and now I'm having the same troubles again.

I hope this can be addressed in an update very soon

Me too. Assuming it's a problem with Yosemite.

Seems to be. Yosemite reminds me of Windows 95 or ME back when I was a Windows user. It's such a failure in so many ways. In a few days, I'm going back to Mavericks, I can't wait to get a perfectly functioning Mac back again!

I also had trouble with this latest backup attempt (preparing to ditch Yosemite). I thought I'd help it out by excluding the ~/Downloads folder from TM, as it contains quite a lot of data. Show yet another bug in Yosemite and a FAIL one at that: The folder will be excluded from backups, all right, as evident by it no longer having any historical snapshots when entering TM. However, the folder and files in it are actually still residing on the TM disk, so no space has been freed (and no space can be manually freed, as you cannot see them in TM, and thus cannot delete them). What a joke.

When people said that Apple would go downhill after Jobs' death, I scoffed. I no longer scoff. This last year or so, every new version of anything Apple I've used has been worse than the previous one.

Hi everybody,

I found out, that it only does the new backup after dismounting and remounting the external drive. So if you left your external drive mounted forever on your Mac (hypothetically) after the initial backup, there would be no issue. I also found out, that it's a problem of the calculation of the changes made to the disk. The calculations are always way off the charts, so on the basis of these wrong calculations, it assumes there is not enough space on the Time Capsule / backup volume and aborts the backup. If there would be enough space on the volume for a full new backup (which you can simulate / test out using a smaller external drive), it would continue with the backup and notice during the backup, that not everything has to be backed up again and would copy only the relevant files. That's why not everybody with external drives notices this issue, only those who have "limited" space available on their backup drive. As I said, I found all this out via the Console logs (see below), with the inspiration of this discussion (Yosemite and Time Machine) and by testing it with a smaller external test drive.

In the meantime I talked to Apple Support but the "normal" staff couldn't help me, so they forwarded my case to some superior "Software" staff, who is supposed to phone me one day, when he has worked something out. I'm still waiting for that call.

So to have a working backup solution for my external drive I connected it to the older Macbook of my girlfriend running 10.6 Snow Leopard, which backs it up just fine. I just have to remember to connect it every once in a while and let it do a backup.

I didn't test out 10.10.2 yet. Did it fix this issue for anyone?

Here are the console logs with the test drive, that show the wrong calculations (the test drive is called "Test", it has a total amount of 30.49GB of data on it, my internal drive is called "Yosemite"):

I'll chime in with another "me too". Using a mid-2012 MBP with Yosemite 10.10.2 and a 2TB Time Capsule.

Console logs:

system.log:Feb 10 07:06:20 MacBook-Pro.local com.apple.backupd[21303]: Backing up to /dev/disk6s2: /Volumes/Time Machine Backups 1/Backups.backupdb

system.log:Feb 10 07:08:30 MacBook-Pro.local com.apple.backupd[21303]: Will copy (216.7 MB) from Macintosh HD

system.log:Feb 10 07:08:30 MacBook-Pro.local com.apple.backupd[21303]: Found 2277 files (276.1 MB) needing backup

system.log:Feb 10 07:08:30 MacBook-Pro.local com.apple.backupd[21303]: 2.79 GB required (including padding), 1.57 TB available

It needs 2.79 GB to back up 276.1 MB?