I have two Macs, one is running Snow Leopard and can't be updated any further. The other is running El Capitan. I use FileVault on the latter and I also want to backup the latter to a 1TB external hard drive using Time Machine.

I want the backup to be encrypted. AFAIK that means I will not be able to access the EC backup on the SL machine. That's OK with me. But I still want to use the remaining space on the drive as storage that I can also access on the SL machine.

Is it possible to have only the backup be encrypted but having the rest of the external drive be compatible with SL? (I.E. unencrypted)

Can it be achieved by making two partitions, one for encrypted Time Machine backups, and one for other, unencrypted storage? Can the latter partition be exFAT formated?

1 Answer 1


yes, two partitions of the same physical drive would allow you to run in this configuration. It would be your best option.

you can partition and format the storage partition to whatever flavor you'd like (fat or GUID, etc)... The backup partition, however, needs to be HFS+. That is the only format Time Machine will work with.

  • Thanks. Just did it. Will hook it up with the SL machine when I get home in a few weeks. BTW, the backup partition needs to be HFS+, right? I think Time Machine requires that.
    – Fiksdal
    Dec 6, 2015 at 16:23
  • I've edited the answer to add the minor detail that Time Machine requires HFS+. Once the edit is peer-reviewed, I will accept the answer.
    – Fiksdal
    Dec 7, 2015 at 2:52
  • yes, HFS for the Time Machine partitions..... make sure when you partition that you set both as GUID (under options, when you're choosing the number of partitions). Also note that making paritions will delete ALL data off the drive, so be sure you've got it backed up elsewhere!! Dec 7, 2015 at 2:57
  • Yes. Important to back up before. I partitioned two different drives. The first time was on Yosemite, with one HFS+ partition and one exFAT partition. That did erase the whole drive. However, when I did it a second time with a second drive on El Capitan, the previous data from the drive was actually kept. The drive had previously had a single HFS+ partition, I partitioned it into two HFS+ partitions. The previous data remained on one of the partitions. But I reccomend that any readers backup their data first anyway.
    – Fiksdal
    Dec 7, 2015 at 5:15

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