I have searched for posts with my specific issue but have not found any, here, or on Google. I hope someone here has some helpful information for me. I have posted this issue on the Apple forums. Thus far I haven’t found what the problem is.
I recently updated my Mid-2012 MacBook Pro directly to Catalina 10.15.5, skipping any earlier versions of Catalina.
I have a 4TB WD My Passport for Mac that I connect via USB primarily for Time Machine.
I first used the drive only for Time Machine and it worked fine for a couple days. I then decided to use some of the space for external file storage and copied several GB of files to it from another drive. Time Machine continued to work fine all day. Then the next morning I had this notification:
“The backup disk is not in Mac OS Extended (Journaled) format, which is required.”
I couldn’t think of any way that could happen, but believed its story. I could not unmount the disk or eject it. I could not even reformat it using Disk Utility. Nothing I tried to get it working helped.
I removed the disc, connected it to a Windows computer and reformatted it. I plugged it back into the Mac and reformatted it to Mac OS Extended format (Journaled) GUID, set up Time Machine and away it went, working perfectly for the remainder of the day.
The next morning I woke to find the same notification again. I found somewhere online that Time Machine may not work properly if there were any other files stored on the same drive with the Time Machine folder. So this time I erased the drive, partitioned it into two 2TB partitions, then formatted them both as Mac OS Extended format (Journaled) GUID. I started Time Machine on one partition and copied other files into the second partition. Time Machine took off and worked fine for the remainder of the day…until this morning when I saw the same notification again! “Time Machine failed because the drive is not formatted as Mac OS Extended format (Journaled) GUID.”
When I look at the disk information in Disk Utility, it plainly says that the drive is formatted as Mac OS Extended format (Journaled). I found via the terminal that it is indeed set up as GUID.
Why is this happening every morning? This disk has always been formatted correctly. What could possibly make Time Machine think it is not?
Why would Time Machine work perfectly all day, taking several snapshots of my computer, then fail every morning? The last successful backup is in late afternoon or evening, then every morning it fails with that false belief that the disk is not formatted correctly.
I do not have any password protected security on the My Passport drive that might keep the drive from working when the computer is asleep. At least there is none that I’m aware of. I never have to log into the drive. The computer stays on 24/7.
I welcome any input that might help me get to the bottom of this.