I suspect you are trying to copy files in Finder that you have previously copied using
rsync (from your included tags, and the screenshot). I spent quite some time a few weeks ago with exactly the same problem, where I was trying to delete files on a Samba share that I had previously copied from Mac to my NAS using
rsync. I'd originally used
rsync for its ability to resume after failure and be a bit more transparent in progress while moving 300GB+ of data, rather than rely on the opaqueness of Finder's progress bar.
A good possibility is that the issue is due to invalid characters in the filenames that were caused by a missing UTF-8 conversion in the
rsync copy. I found this with a lot of accented characters in the filenames of a lot of music files (too many Krautrock umlauts...). When viewed in Midnight Commander via the share, the first character was invariably invalid and represented as
?. Finder did not show the filename as invalid, but refused to touch it otherwise with the same error you are experiencing.
Apparently there are different 'Normalisation' forms of UTF-8 encoding, and macOS uses an Apple specific one which needs to be accounted for in any
rsync copy to a non-macOS machine.
There is a good explanation of the problem in this Question.
Rsync with Linux server: special character problem
And the (very) technical explanation for different Unicode Normalisation Forms here. It's to do with methods for string comparisons, amongst other things.
Apparently the conversion should always be
--iconv=utf-8-mac,utf-8 regardless of direction. This is because the order is
--iconv=LOCAL,REMOTE, not from, to . As the local is always macOS this works as expected.
Now, you did not specify whether the external disks were attached directly to your Mac, or whether they were hosted on another machine. If they are on another networked machine you will probably have to work with them directly on that machine. If the disks are local (HFS+ or APFS) you might be able to 'fix' the affected files by attempting an
rsync local-to-local copy using the
--iconv=utf-8-mac,utf-8 conversion. I have not encountered this with locally attached disks so cannot provide any sort of guarantee.
rsync -aivP --iconv=utf-8-mac,utf-8 local_source local_destination
Also, ensure you are using a current version of
rsync. The one supplied with Ventura is too old, so use one installed from Homebrew or similar. The
utf-8-mac conversion is also specific to the Mac versions of
iconv and won't be found in a Linux version.