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rbphotg2
User level: Level 1 (4 points)

NAS Server won't allow files to copy after Mac OS 27 installation

Since upgrading my M5 16" MacBook Pro to OS 27.01 I can't transfer files to my NAS Server. I get this message: (You can’t copy the item “RRB02003.xmp” because its name is too long or includes characters that are invalid on the destination volume.)

I have used this server for two years with no issue. What gives?

Richard

Posted on Sep 30, 2026 4:19 PM

2 replies

neuroanatomist
User level: Level 9 (72,871 points)

Sep 30, 2026 4:49 PM in response to rbphotg2

Can you copy files from your NAS? Ensure that your NAS is connected via SMB. One important point is that macOS 27 Golden Gate does not support Apple Filing Protocol (AFP), and while that networking protocol worked with macOS 26 Tahoe, it is no longer be supported by Apple starting with macOS 27. That's the reason anyone who upgrades to macOS 27 and has a Time Capsule, which can only use AFP, now owns an aesthetically-pleasing paperweight. AFP was actually deprecated years ago (starting with Big Sur on the server side), and Apple started warning users with a Time Capsule about the client-side deprecation in macOS 15 Sequoia.


Many NAS systems offer support for AFP, the QNAP NAS that I used to have did and the Synology NAS that I currently use does, too. If that's how you set yours up, go into the settings on your NAS (typically accessed via a browser, though many vendors offer a 'helper' app like SynologyAssistant that I use to launch that browser), and change it to use SMB3.


I suspect AFP is the issue, not the filenames. But just in case, even though your example file name RRB02003.xmp looks short, macOS calculates the entire absolute path (from the root of the network share down to the file), and that may exceed the length limit. Alternatively, if macOS detects a hidden invalid/special character (like a colon, question mark, or invisible space, not that I see any in your filename) the file may be rejected before sending it to the server.


How to Fix It

  • Shorten the destination path: Move the target folder higher up in the NAS directory tree so the overall character count of the file path drops. 
  • Check for hidden characters: Inspect the folder name on the NAS where you are dropping the file; avoid special punctuation, symbols, or reserved terminal characters. I find that pasting the filename in a the URL field of a web browser or the title field of an email effectively clears any special characters.
  • Copy via Terminal: Bypass Finder's strict pre-flight checks by using the command line tool cp or rsyncin the macOS Terminal app to force the transfer over the network


Personally, I have a Synology NAS that I use for both Time Machine backups and as a general file server, configured to use SMB3. I typically use DxO to process RAW images, but I renamed one of my recent RAW files to your filename, then opened it in Photoshop (ACR) so it created a .xmp sidecar. I was able to drag-and-drop the RAW file and the .xmp sidecar to the NAS with no issues.


MrHoffman
User level: Level 10 (169,253 points)

Sep 30, 2026 4:45 PM in response to rbphotg2

Which NAS operating system?


Checked for NAS operating system / firmware updates?


Do different variations of the name copy?


How long is the filename?

Originally posted at discussions.apple.com/thread/256368171