I'm a professional freelance editor who works with ... let's say "aspiring" authors, with Track Changes dealing literally with several thousand edits over 100k-word manuscripts, and once a certain level of edits is reached, Word starts to freeze, the display turns fragmented mush, things like word or sentence selection is unstable ... generally the app is unusable. It's really frustrating considering I was using Word 2007 and figured it was the responsible thing to do to upgrade.
A Microsoft tech tried to help remotely, suggesting workaround fixes (like tweaking how TC mark-up is displayed), but really I shouldn't have to "work around" anything. It's like Word isn't designed for documents longer than 10k before it begins to flake. That's unacceptable considering that Word processing is relatively easy compared to, say, 3D apps.
Is there any fixes or settings I can try to make Word stable? I've done the graphics fix (which is only in the Outlook settings anyway now).
I'm only assuming it's the high amount of Track Changes data causing the problem, but turning TC off doesn't help once it starts failing — and it's obviously not an option anyway.
Thanks for any help.

It may be that Office 365 has a bug that causes the issue. I know you shouldn't have to resort to the following suggestion but, if your job relies on it, then maybe consider buying an installed stand-alone version of Office? Maybe Office 2019 or the latest 2021?


Just a suggestion.

Well, it's a welcome suggestion, but with Office 365 aren't I getting the latest version of Word? A standalone version is only a different payment method? I'm getting the same product? By the way, I have tried disconnecting the net to see if the issue is in syncing, but no joy, and saving to my PC instead of to One Drive makes no difference. Thanks for your thoughts.

Here follows an extract from How Big Is Too Big for a Microsoft Word Document? . Could it be relevant to the files you are working with?

"Word documents that are half a gigabyte are going to be extremely difficult to work in, especially if the bulk of the file contains images or videos. However, a lot depends on your system resources, and whether your computer is capable of working with files that large.
It also depends on Word itself. While the program is typically stable for general use, you might find it significantly less so if you try to work in or save a file of a substantially larger size than usual."


Do you have plenty RAM and an SSD (not an HDD), processing power and a decent graphics card?

With Office 365 you are getting the latest version.

That does not mean you are getting a version without bugs. Sometimes, "improvements" to 365 have unintended consequences (bugs).