I expect to wait a long time before updating to macOS 10.15 (Catalina) but I am doing some preparation for my iMac environment. Today I want to report on Time Machine. (I am running macOS 10.14.6 Mavericks)
This week I looked at the file format for the various hard drives in my system. My 2017 iMac is formatted in APFS (must have come that way when I bought it). All my other external hard drives (2 Super Duper clones and 2 Time Machine drives) are in HFS Extended
I understand that Super Duper is not Catalina compliant at this point so I didn’t touch those drives
One of the TM drives is small (500 GB) so I decided to change the file format to APFS using Disk Utility
That worked as expected. NOTE THE PROCESS ERASED THE PRIOR HISTORY.
I had an APFS external hard drive that I “attached” to the Time Machine routine in System Preferences.
To my GREAT surprise I next received a system message that the drive format was incompatible AND it proceeded to change the format to HFS Extended.
I have looked at the drive and it is back to HFS
So the Time Machine process (in Mavericks at least) does not work with APFS drives.
Is this true in Catalina also?