My backup hard drive won't work now after upgrading to Catalina

[phoenix_jet]

So I upgraded to Catalina on my 2009 MacBook pro by the backdoor method and now my external hard drive won't work. Just cycles and never goes into actually backing up. Just continues to say "preparing for backup."

Is this a known issue? I know Apple wouldn't support my upgrade b/c they want to sell me a new machine. Do I need to get a new external drive? And yes, there's plenty of space on this drive.

Thank you.

 

[chscag]

So I upgraded to Catalina on my 2009 MacBook pro by the backdoor method and now my external hard drive won't work. Just cycles and never goes into actually backing up. Just continues to say "preparing for backup."

Reformat your external drive to APFS and start over with Time Machine.

 

[appltech]

Try creating a new partition for backups using Disk Utility and back up to that instead. Also, as @chscag mentioned, make sure the file system on that volume is APFS (although TIme Machine reformats it for you automatically)