Time Machine Couldn't Complete The Backup - an error occurred while copying files

I have been struggling with same issue on a brand-new non-partitioned external drive. Apparently this is a common problem and “Apple is working on it." In the mean time, I am using SuperDuper! which is useful but does not do quite the same thing.

I am resigned to waiting for an Apple fix.

mrchntmarine wrote:

So im on a new 2019 16" MPB W/ Catalina and I have experienced odd behavior with a new partitioned WD external drive I use for Time Machine Backups. All partitions are formatted Mac OSExtendedJournal The below error message being the latest issue. Can anyone tell me how to find the cause and remedy? Apple C/S says that I shouldn't be using multiple mounted partitions on the dest. drive while Time Machine is in use.... Doesn't sound right to me.

Tks for any help! ........

https://discussions.apple.com/content/attachment/dd4f5ed9-0234-41cd-98e6-50a29f281179

Time Machine: How to transfer backups from a current to a new disk ... - Apple Support-

https://support.apple.com/en-us/HT202380

Another example.

Not meaning to piggy-back on your woes, but my new 202 27” iMac with new 2 TB un-partitioned Mac OSExtended Journaled WD external drive does the same thing.

It also tells me that I’m backing up from an encrypted disc (is that the T2 chip talking?) to an unencrypted disc.

We and many others are not making this up. The best discussion of the problem that I’ve founds far is here:

https://eclecticlight.co/2020/02/12/time-machine-in-catalina-10-15-3-has-serious-bugs/

Thank you for your kind reply but my situation is much more simple.

I am using a brand-new 2 TB WD drive connected directly to the back of my iMac: no hub, no dongle no nothing. The backup always craps out about 30% of the way through.

I am using SuperDuper! with great success, so I don’t think I have a hardware problem.