I am getting this message while running 10.11.6, El Capitan OS.

I have updated to latest version and still getting this message.

The BETA does not resolve the issue of the message "This file has been modified outside of Illustrator". I just installed it and the problem showed up immediately. This is truly annoying. If it is related to the latest Mac OS update, then it would be good to know that for sure. So far, Apple seems to think it is an Adobe problem. It only shows up in Illustrator, at least in my experience so far.

The fix works for me, thx heaps it was driving me nuts!

I don't think this is an Adobe problem; I get the message saving a file in TextWrangler to my HD even immediately after creating a new file. It must be some problem with the Mac OS 10.13.3 update...

Same problem.. saving to HD. Driving me crazy....

I'm also having this issue and am not working on a network or saving it to the cloud, online drives, or a removable drive. I'm just saving it to my machine's hard drive. I would say it happens 90% of the time when I use Illustrator.

I'm having the same issue.
Not saving to Dropbox, just on to my hard drive.
Doesn't happen on every save of the same file. Seems pretty random.

Same issue here, I'm just saving to a drive. Every time I copy and paste (and yes I embed the file) items I get this error. It drives me nuts.

This happens to me and I'm not using Dropbox, but I am using Google Drive desktop app for Mac.

I'm saving to a Dropbox folder and getting the same message even now, February of 2018.

I am having the same issue but intermittently, i.e. on some files only.

I seem to get this notice all the time! I'm not using dropbox or anything else.
I'm opening a file that i used a couple of months ago, do something to it and every time I go to save, I get this notice.

I have even gotten the message on new files I create.
Everything is done on my desktop — nothing is shared.
It is very annoying!!!

Same problem all the time. I can work new file and save a few time, but if I copy, paste or import anything... from local drive, even from same folder, then the message comes up every time I save. MacOS 10.13.3, Illustrator 22.0.1 I do NOT use iCloud back up. All files are on an external pro Lacie drive.
PLEASE HELP! This is annoying and killing time when your using Illustrator all day.

I'm continuously running into this issue. Yesterday, I created a file locally, did some design stuff, saved the file, and ran into this prompt.

I'm on MacOS High Sierra 10.13.3

For, for me this issue occurred when I imported the existing preferences from CC 2017. As soon as I uninstalled/reinstalled Illustrator and chose not to import existing preferences or settings, I did not get this dialog box any longer.

Honestly, installing previous preferences/settings seems to be buggy in many ways so i always choose to start from scratch.

I'm having the same issue after upgrading to MacOS 10.13.3 and using the latest illustrator (22.0.1). Adobe take note of your user's comments and provide seamless implementation of illustrator basic functions before adding superfluous (and sometimes outright silly) content to the interface. After so many updates basic node selection is still shoddy, and overall the program is more unstable than ever. Cut the clutter or go down as the new Corel draw phenomenon.... :-)

I have the same issue with the error "this file has been modified outside of Illustrator," even though it has 100% NOT been modified outside of Illustrator. The issue began immediately after I upgraded to High Sierra 10.13.3. My files have always been backed up on Dropbox and no other user has access to these files but me. I never had this issue before the upgrade and I'm using the same files from the same location. (I use CS6 so please do not tell me to upgrade to CC. Our company is too small to pay an extravagant monthly fee for 2 users). Please fix ASAP! Thank you.

I also have this issue. I only have Illustrator open - no other Adobe products or other third-party programmes. The only adjustment I made was to save the changes to the file as 'Save As' and rename it as a 'v2'. This has been occurring since I upgraded to High Sierra. I'm working off our local server, but I've been doing that for the last 15 years.

Funny how you continuously shove the CC Library syncing down our throats but still can't get the basics right - I've seen this issue in threads going back to 2012.

Yes, just got the new macbook pro and this just started happening. Not using dropbox files or google drive, everything is on my hard drive. The files have 100% NOT been modified outside of Illustrator.