I desparately need to migrate from Mac OS X 10.5.8 running on a rather old Mac Pro to 10.10 running on a new Mac Mini. To achieve this, I was planning on using the Migration Assistant (MA) tool with a Time Machine (TM) backup stored on a USB drive. However, MA keeps telling me that there is not enough space to complete the migration, even though the TM backup is ~24 GB, and the Mac Mini comes with a 500 GB HD.

I have checked here:


but none of the advice given there help me. I have also checked the disk (multiple times) using diskutil.

Do you guys have any tips on how to resolve this? Are there any other ways in which I could perform the transition?

Thanks a LOT in advance!

EDIT: I have tried to connect the two machines via FireWire - same issue. In the dialog box where I can select what to migrate, I have tried unselecting user data, applications, etc. What's strange is that MA keeps telling me I have not enough space on the target drive even if I unselect everything except for, say, the settings.

  • The Apple discussion you quoted is of no value. Apple discussion groups are just to discuss, not to fix anything. They aren't targeted toward finding an explanation or a fix, as StackExchange is.
    – dan
    Aug 21, 2016 at 21:45
  • Could you check what your target MacOS X (Yosemite) is writing within /var/log/system.log at the time of this error? I suggest you to open Terminal and run /usr/bin/sudo tail -f /var/log/system.log.
    – dan
    Aug 21, 2016 at 21:52

5 Answers 5


The same thing happened to me. I lost a Mac virtual machine, which was not backed up by time machine on the host system, but it WAS backed up by the guest OS X system itself. After creating a new guest OS X system and figuring out that Migration Assistant was the correct method of restoring from a Time Machine backup, I was blocked by the same issue. MA claimed that I needed more space to restore the data from the backup. My target system was a single drive system with 80GB of total space and 60GB free, while the backup was only around 30GB in size. Even when only a small amount of files were selected, MA refused to restore it.

The target system had Server.app installed, while the original system backed up did NOT have Server.app installed. So, I simply moved Server.app to the Trash, and tried MA again... this time it worked and had no issues.


I have been having this problem when using Migration Assistant to move from a 10.6 install to a 10.11 install, and could get nowhere.

A reference in this discussion: https://discussions.apple.com/thread/7523071?start=0&tstart=0 to Charles Edge's TakeControl of OSX Server book seemed to indicate that it might be a "Server.app" issue. For me, the old 10.6 system was not a "Mac OS X Server" machine, but the new 10.11 system did have the Server.app software installed and running.


When I removed "Server.app" from the /Applications folder, and gave my admin credentials, the system informed me that it would turn off all the Server services, but leave the data intact at /Library/Server. Now when I run Migration Assistant.app (after using sudo hdiutil attach /Path/To/Image.dmg to get the sparse disk image with the TimeMachine data to remain mounted after Migration Assistant.app logs me out as mentioned http://www.blueboxmoon.com/wordpress/?p=854 ), I am able to select various items without the claim that there is not enough room.

I just (2016/08/21) did the migration and it has successfully completed with no errors about being out of space.


Have you tried directly connecting the old Mac and the new and using Migration Assistant? Rather than trying to move EVERYTHING (which takes a long time) do it in stages e.g. move user data only.

  • I have edited my question to clarify. Jan 5, 2015 at 14:41

Let's try this to reset TM:

  1. In TM Preferences, put the slider to OFF
  2. Open the backup disk > Backups.backupdb > your Mac’s name > drag to the Trash the folder “Latest”.
  3. In /Macintosh HD > Library > Preferences > drag to the Trash the file com.Apple.TimeMachine.plist.
  4. In the TM Preferences panel click Select Disk, choose the disk again as Backup Disk and everything should be fine.

• A new backup will be taken.


Use an external disk. Install a base system and migrate to that disk. Boot up from the external disk. Move larger data stores off and out of the disk. Things like the mail folder will be large (/Users/YourName/Library/Mail), the mobile sync folder (/Users/YourName/Library/Application Support/Mobile Sync), etc., If you have lots of photos and music, next copy the iTunes folder to the external disk and delete the iTunes folder in /Users/YourName/Music/<iTunes>, follow by copying the iPhotos folder along with the Photos folder located in /Users/YourName/Pictures/<iPhoto Library> and /Users/YourName/Pictures/<Photos Library>

iTunes, iPhoto, and Photos all allow you to hold the option key during launch to select a new library location. This means you can store them on an external disk. You can decide if you want to leave them on the external disk you moved them to or move them back if there's enough space on the new drive. To do that press the option key and click on their respective icons in the dock. Just before the programs launch you will be presented with a screen to choose the location of the library container.

Typically I find that moving only the music and photos give a huge space savings and that should be enough. If it's not then...

Find large files by sorting from largest to smallest size. Make notes regarding the path to the files before removing them and saving them on another disk. Do the migration from the external (now trimmed down disk) then move the files you temporarily stored elsewhere into their proper locations. Let me know if you need clarification or additional help with this.

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