error code 36

Is the file system format of the external drive exactly the same as on the internal drive? MacOS Extended (Journaled) and not case sensitive, if the format of the internal drive is case insensitive? If the file system format is different, some files can be creating the error -36, because the file names may not work on the external drive.

You can check the file system format for each drive with "File > Get Info" if you select the icon of the drive in the Finder.

I am having this issue too.

I tried backing up my ~/Movies directory to an external NTFS drive. The total copy was ~44 GB; however, 90% through the copy I got the following error:

I then moved the copied folder (/Movies) to trash. I then emptied the trash and received this following error:

So what is going on here and how do I clean up after it?

You can not have the Photos library on a drive formatted NTFS - if must only be on a drive formatted Mac OS extended (journaled) or APFS - Where is it safe to store a Photos Library? Requirements for the external drive

LN