A family of Microsoft word processing software products for creating web, email, and print documents.
Good news MS Office users... I can confirm that there IS a solution to this, for MS (Office) 365 subscribers at least.
Firstly, I've just wasted two and a quarter hours of my life in a text conversation with Microsoft tech support, who did not have a clue how to actually disable Copilot. I repeatedly said that the recommended actions don't work before they finally stopped barraging me with all the usual useless, unwanted "I'm sure I can help you to solve this", "Let me see what I can do to help", "I hope you're having a great day" platitudes.
However, I eventually discovered this solution. Be aware that it wasn't free, but for me it was worth it:
I sign outed of MS Office apps.
Went into my MS 365 account, made sure auto renewal was turned off and cancelled my subscription.
I signed up for an MS 365 CLASSIC (or MS 365 Family CLASSIC) account. These Classic accounts do not have the Copilot and other AI functionality that MS is trying to force on us all.
The Classic subscription may not be offered on every account page (it wasn't on mine. I had to contact MS sales).
Once I had signed up to the Classic subscription and it was confirmed, I started up one of the MS Office apps and signed in.
Copilot was gone. For me, anyway.
A couple of caveats:
I'm using Office for Mac (today has highlighted one of the reasons why I infinitely prefer the Apple to Microsoft ecosystem), but I'm assuming it will work for Windows users.
I had to sacrifice three months of my pre-paid MS 365 account, so it wasn't a free solution.
In the end I had to get MS Accounts to cancel the previous account, who tried very hard to do as little work as possible by getting me to wait until it expired. I had to insist they cancel it immediately.
But Copilot is gone and, as someone who spends 12 hours or so a day with their face in Word and Excel, I'm happy.
PS One more thing... the Classic subscriptions cost less than the standard ones with all the unwanted AI rubbish.