Outlook: Cannot move the items. The operation cannot be performed because the message has been changed.

Okay so I did this and it seems to have fixed it for me. I use 365 too and this issue has been driving me bonkers.

When I set up 365 I added four accounts. Added their passwords etc.

I had already unchecked the 'when a reply modifies the original" and it didn't fix it.

I went to File>Account Settings>server settings for each account and found I had to-for some unknown reason- re-provide all my account approvals/passwords.

I then went to File>Account Name and Sync Settings> and UNCHECKED "Purge items when switching folders online"

On the same screen, I have "Mark items for deletion but don't move them automatically" checked.

I had previously checked and unchecked every other setting I had to no avail.

However on sending myself an email using the above combo-I was now able to archive, move, delete or move it about with no issue.

I am still showing all my labelled/categorised emails set up in Gmail web with no issue.

I then went to have a celebratory coffee, using choice words under my breath.

Amazing. Thank you SO much for this!

I had been fighting with this issue for SO many years. Reported countless times to M$ but never a (useful) response, just the usual stuff like we saw in this thread.

For me it would always happen after saving an attachment from an email then trying to move the original email. Usually clicking another email and then back to the original would work, but worst case I would have to restart Outlook. SUCH a pain.

Switched those two folders off in IMAP yesterday and no problems since. Fingers crossed...

I keep seeing this issue, too. I always need to restart Outlook for this, it's terribly annoying and costs a lot of time. It's ridiculous that a problem like this exists and hasn't been taken care of, yet. Microsoft should finally address this.

If your problem still hasn't been solved, I suggest you submit a feedback (if you haven't done so yet). See how do I give feedback on Microsoft Office?

This is to let Microsoft developer team know your problems and improve the products and services.

Before I reply to you, I tried to search for similar questions in Microsoft community and I came across this: "The operation cannot be performed because the message has been - Microsoft Community

Most of the methods I suggest you try are what I found from the responses below. I'm unable to reproduce your issue on my own computer, so I'm not sure what exactly is causing this problem. But I think they might be helpful, so I listed them here.

In theory, Microsoft 365 should be updated automatically indeed, but in fact I just manually updated my Microsoft 365 to the latest version last week because the automatic update didn't work. That's why I suggest you to check the Office version.

If you haven't tried 1-6 yet, try it. Due to limited conditions and that the post was published long ago, I can't guarantee that your problem will be solved immediately; but it is worth a try.

Also, there's another way: removing third-party add-ins (especially add-ins from Adobe) in File > Options > Add-ins > Manage COM Add-ins(Need to Click "Go"), as the post mentioned above says.

If this problem still can't be solved, please tell me if your e-mail is IMAP, POP3 or Microsoft Exchange account, with the steps how you try (You can record it with steps recorder).