macOS Big Sur - I have an external hard drive with Time Machine backups from my prior Mac. I am simply trying to copy a few files from my old Mac (located inside the backups.backupdb folder) to my current Mac. I have tried this by simple copy/paste via Finder from the external hard drive, as well as browsing the external hard drive from Time Machine on my current Mac, and doing a restore. In both cases, I get an error 36 in Finder - specifically "The Finder can’t complete the operation because some data in “file.mp3” can’t be read or written.."

So then, after some research, I was actually able to get the copy/paste function to work by using terminal and the cp -R command. So now the needed files are on my current mac, but if I try and open any of them, I get an error message about the file not being compatible.

Now I'm attempting to see if this is a permissions issue. Whereas most files on my mac list me as Read/Write permissions in Get Info, these copied files do not. Here is what the Get Info Permissions looks like on these files:

Get Info Permissions

If I try and add myself to the Permissions list via the plus button of this window, I get another error 36 - the operation can't be completed. How can I get myself on this permissions list? I have already tried First Aid in Disk Utility on the external drive, and while it said it ran successfully, it did not update the permissions.

UPDATE #1: I was able to add myself to the Permissions of the files on the external hard drive. The errors still persist, however.

  • I have my suspicions that this may have something to do with Big Sur expecting a TM drive to be APFS, yet all earlier OSes used HFS+
    – Tetsujin
    Oct 9, 2021 at 8:55
  • @Tetsujin I would have to agree with you. This is a real doozie. I can not get the permissions to change at all. Any ideas?
    – Stpete111
    Oct 9, 2021 at 16:54
  • Guesswork: Switch off Time Machine. As you've managed to gain permission to copy files off, do that. Grab BatChmod & use it to clear down permissions, ACLs, xattrs etc of the files you copied off.
    – Tetsujin
    Oct 9, 2021 at 17:01


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