You'll need to provide more details (specific steps, your operating system and word processor, etc.), but I'm sure someone here will be able to help you. (I'm just commenting so that you can add this information by the time they have a chance to look over your question and will have enough information to help you.)
The only thing that comes to mind might be if you're having trouble adding citations in Word after the recent Zotero update, which should have been fixed, but if you're having those same issues you could reply there (it sounds like it might not be fully fixed for everyone yet): https://forums.zotero.org/discussion/77815/urgent-error-with-word-for-mac-2011-and-zotero
"Zotero experienced an error updating your document." That doesn't tell me how to fix it and the troubleshooting doesn't help. It was working earlier today. I don't know what happened. Also, I can't change the Zotero version.
@MargaretKimberley: The other thread was specific to Word 2011 for Mac and was fixed, so let's keep the discussion in this thread.
You don't say what the problem is, but unless the problem still occurs in a new document or after completing clearing a copy of your document, you still need to follow the Debugging Broken Documents steps.
Because of how Track Changes works, it can interact in weird ways with the changes Zotero needs to make to the document, so turning it off has always been the first recommended troubleshooting step — linked from the error dialog you received — when encountering a problem in a document.
There's no "once again" here. As I say, this isn't a new issue, there's nothing specific about the Zotero version here, and the other thread you posted to — about a very specific, brief bug with Word 2011 for Mac — wasn't relevant. It's possible that this could be improved in some future version, but as things are and have been for years, turning off Track Changes is just something you may need to do to use the Zotero plugin reliably.
The only thing that comes to mind might be if you're having trouble adding citations in Word after the recent Zotero update, which should have been fixed, but if you're having those same issues you could reply there (it sounds like it might not be fully fixed for everyone yet):
https://forums.zotero.org/discussion/77815/urgent-error-with-word-for-mac-2011-and-zotero
It was working earlier today. I don't know what happened. Also, I can't change the Zotero version.
You don't say what the problem is, but unless the problem still occurs in a new document or after completing clearing a copy of your document, you still need to follow the Debugging Broken Documents steps.
Thanks but this is very disturbing. I have used zotero for 3 years without incident.
Thanks again.
I hope that this problem is fixed and I can once again track changes and still use zotero.