I just got a new iMac with 256G SSD + 2T regular HD.

The data on my old computer is bigger than 256G

Not only that, but the Migration Assistant seems to want to migrate-to the SSD only.


EDIT I wasn't clear -- I know which data I want on which device, I was trying to cajole MigrationAssistant into splitting it up for me.

It turns out that the problem was my misunderstanding of "migration." I thought it was "migrate your system from old machine to new", but it's really "migrate your user-prefs & settings (mail, printers, etc.) to a new system", with an implied "all that data stuff is yours to deal with."

MigrationAssistant will move "other files" if you want, but I guess I wasn't getting that this was sort of an "oh, by the way" thing, and not its main function.


2 Answers 2


First, I'd suggest making a plan for deciding what data is going where. A simple starting point is put all your media (particularly videos) on the hard drive, since it often accounts for the bulk of the data and benefits less from the speed of the SSD.

Secondly, you can customize what data Migration assistant brings over. Have it transfer your apps and settings, and maybe the basics from your home directory, then once you've got your system up and running you can transfer the rest either by running Migration Assistant again, or manually via Target Disk mode.

Another option, if you have a bunch of data (enough to get you under the 256GB barrier) that you know you're going to be putting on the HD, is to transfer it manually first (or to a backup drive), then delete it and run Migration Assistant without any exclusions.

  • This seems like good advice. It is disappointing that Apple hasn't built in a solution to this in their Migration software.
    – dan8394
    Aug 26, 2011 at 6:27

The Mac Transfer Assist transfers the files from the old Mac to the new Mac, choosing the location where the OS is installed. If OS on new Mac is installed on the SSD, you may have a problem if the files are too large.


  1. backup everything
  2. restart new Mac holding down the Alt key. Choose the "Recovery HD" disk
  3. choose "Reinstall OS X", and make sure it is installed on your normal HD drive
  4. Once completed, use Transfer Assist on both computers following the instructions. Your files will now be moved to the normal HD on your new computer.
  5. When completed, repeat steps 2-3, only this time you install the OS on your SSD drive. An advantage because OS will then run faster.

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