This is still an issue, and a critical one!! (Illustrator Version 26.4) It's not just an annoyance. I am currently editing files for print production that were saved as editable pdfs. When I now select "discard changes", the changes I made are discarded. When I select "keep changes", I cant edit the file as a multi-page editable PDF but it is treated like one that wasn't saved with editing capabilities. That means I am losing all the work that I did in the past days. Please provide a fix for this immediately!

It's Baaaaack! I can reproduce it reliably when I Save As and then edit the new file.

Illustrator 26.3.1, Monterey 12.4, Mac Studio

Here's my best guess...I'm having the same issue and based off the other responses:

It happens when you are working off a remote server, either GoogleDrive, BoxDrive, OneDrive, etc.

These drives manifest as synched folders on our desktop, even if we appear to be working directly off the drive. As synching happens almost continuously now, and files get 'marked' by the particular remote drive, that very minor update to the file is what triggers this. It's as if you and a colleague were sharing a file through Creative cloud. The trigger is meant to warn you.
Instead in the majority of cases it's an ongoing annoyance.
Best guess.

we are running 3 brand new imacs on OS 12.1, and have the latest version of Illustrator (26.03). This happens on all the imacs almost all of the time. We also get temp files that we cannot delete unless we restart the macs. We didnt have this problem before we installed the new macs.

I am running all applications and OS fully up to date on a brand new iMac, syncing to OneDrive as I always have been, I am the only person using Illustrator in my company, and I get this annoying message every time...

I am running 12.0.1 Monterey with Illustrator CC 2022. I usually get this issue when I save files into Google Drive and open them. It's really frustrating because I am the only one with access to the file.

I hope Adobe can solve this bug.

nice try but no, still around in v26

26.0.1 version and this **** is still happening. Saving
in macOS to a folder synced with OneDrive. But cloud has been around for a while now, isn't it?

Edit: Obviously nobody else is not editing that file, just created it.

Still getting this error. MacBook Air M1, Monterey (12.0.1), Illustrator 26.0. Saving to Google Drive.

Still an ongoing problem that hasn't been resolved with any of the latest software updates. Been dealing with this message for years now—on AI files that have never once been opened or even placed in any other program. Please fix!

Still happening. Any update?

Still happening in version 25.4.1 ☹️

The issue still persists in version 25.3.1.
Files saved to Microsoft OneDrive (Mac version).
When the file is moved outside of OneDrive there is no alert message.
This is EXTREMELY annoying and counterproductive!

Macbook Pro Big Sore 11.4

I still get this alert on an 2019 Intel MacBook Pro, Big Sur 11.4, Illustrator 25.2.3 saving to a Google Drive.

Why can't this problem get resolved??? Guess deaf ears or selective hearing is the problem.

Also to add, this doesn't happen with saving direct to Dropbox or iCloud, just OneDrive.

Ended up here looking for a fix for the 'This file has been modified outside Illustrator' message.
On the current version of Illustrator 25.2.1
Mac OS 11.2.3

I only get this issue when saving to OneDrive.

Yes I have constantly had this issue for 2 years now from OS 10.13 and even through to now Big Sur OS 11.2.2 . It seems to happen anytime I am working on any Illustrator files that are directly saved on a cloud service - I have seen it on Google Drive, One Drive, and also happens when saving directly to my Mac Desktop - which is sync'ing to my Apple iCloud account. I am running the very latest version of Illustrator. According to my Creative Cloud account I am up to date with version 25.2

Also confirming issue still exists. Using version 25.0.1 with Mac 10.15.7

Very annoying. If Adobe can't fix, please explain why.

It's back again with Illustrator 25.2.