Can't reliably add attachments in Tahoe Mail

I have an M2 Max Studio running Tahoe, and ever since updating I can't reliably add attachments to emails. I almost always get the error message posted below. I say almost always because when I had this problem a few minutes ago, I restarted my computer and was able to attach the PDF. This makes me think it's some kind of system resources problem, though my computer had only been on for about an hour when I got the error and, while I was running a few programs at once (Illustrator, Bridge, Podcasts, Safari, and Mail), it was not more than I run on a typical day and would have been running with Sonoma which never had this problem.


The files are uniformly fairly small, all under 3mb or so, and this latest error was produced by a PDF that was 520k, so I don't think that size is the culprit.


Is anyone else having this trouble, or does anyone have any ideas how I might address it?



I saw that one other user seemed to have this problem, but no one answered their post. I'm hoping I'm luckier. Thank you!



[Edited by Moderator]

Mac Studio (2023)

Posted on Sep 18, 2025 11:24 AM

Reply
8 replies

Sep 26, 2025 12:08 AM in response to TomDeja

Hi,

I’m running into exactly the same issue with Mail on macOS 26 (Tahoe) and M2 Ultra Studio : attachments almost always fail, sometimes a reboot fixes it once, but then the problem comes back.

Here’s what I’ve already tried, without success:

  • ✅ Turned macOS firewall off (also tested with it on/off, removed and re-added Mail rules).
  • ✅ Tested on two different networks: fiber (Orange) and iPhone 5G hotspot → same result.
  • ✅ Cleared Mail cache and Mail Downloads folders.
  • ✅ Rebuilt the Envelope Index.
  • ✅ Removed and re-added accounts (Gmail + o2switch professional account).
  • ✅ Tried another mail client (Spark) → same issue with attachments.
  • ✅ Sent via webmail (Gmail web + o2switch webmail) → works perfectly.

All of this strongly suggests the issue is tied to macOS Tahoe 26 itself, not to the servers, the network, or account settings.

👉 Have you found any lasting solution or workaround (other than rebooting every time)?

Thanks in advance!

Can't reliably add attachments in Tahoe Mail

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