MacBook – simply swap a Time Machine SSD with the original one on an MBPro

backupmacbook protime-machine

I need to replace the original internal SSD (256GB) with a 512GB that has Time Machine on it and up to date.

I am hoping it were not required to involve yet a third disk – e.g. another USB hard drive in this process .. but am not clear on it. Let us call this 1TBdrive

Specifically it seems one solution would be:

  • attach the 1TB hard drive and make it the time machine backup.
  • power off the MBPro and physically swap the 256GB with the 512GB
  • attach the 1TB USB hard drive and boot up, keeping the option button pressed to induce booting to time machine
  • restore from 1TB TM to the new 512GB internal drive

Unfortunately I do not possess this 1TB external drive. So is there any way to do this with just the first two SSD's?

UPDATE Here is the relevant available disk space info

df -k

Filesystem                        1024-blocks      Used Available Capacity  iused    ifree %iused  Mounted on
/dev/disk1                          243915264 235014420   8644844    97% 58817603  2161211   96%   /
/dev/disk7s2                        499771696 214002444 285769252    43% 53500609 71442313   43%   /Volumes/os2mellyrn

Notice the externally attached SSD used for TM (disk7s2) still has 280GB available = more than twice the internal (active) SSD (disk1)

Best Answer

Sure it works but you have to create, clone/TM-restore and erase various volumes:

I assume your internal disk is disk0 containing disks0s2 as your internal start volume and your external disk is disk1 with disk1s2 as your Time Machine volume.

Without loosing your TM Backup:

This only works if the sum of used space on your TM-volume and used space on your main volume is smaller than ~ 500 GB (to leave some recommended free space on the interim main volume disk1s3). In your scenario the sum is ~449 GB so it works.

  • Add a partition (disk1s3) on the 512 GB SSD with the size ~256 GB (by splitting disk1s2). That should work without erasing disk1s2
  • Clone disk0s2 (your current main volume) to disk1s3 (or restore your TM-backup on disk1s2 to disk1s3), then restart from disk1s3
  • Erase disk0s2 and clone disk1s2 to disk0s2 (or backup disk1s3 to your now new TM-volume disk0s2), then erase disk1s2
  • Clone disk1s3 to disk1s2 and restart from disk1s2
  • Delete disk1s3 and expand disk1s2 to the full size. If that doesn't work start from disk0s1 (your internal Recovery HD) or to Internet Recovery mode and try again.
  • Just reinstall your current system on disk1s2 to create a Recovery HD if none is existing without loosing any (personal) data (e.g if you are running 10.0.2 now just download the latest Yosemite installer and reinstall).
  • Swap the drives

Loosing your TM Backup (not recommended):

  • Erase disk1s2
  • Clone disk0s2 to disk1s2 and restart from disk1s2
  • Just reinstall your current system on disk1s2 to create a Recovery HD if none is existing without loosing any (personal) data.
  • Swap the drives
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