Why does signing out suddenly de-activate office?

DDK try this as a workaround.

Close all but one open Office 365 application (I often have several windows open)

I signed out of 365.

Unplugged the internet

closed the application

started it again

It starts OK for me, just cannot access internet AI features like Dictate in Word.

.

I plugged the internet back in and when I start Word, it goes

Stefan: 

You can indeed sign in while connected to the internet, then disconnect from the internet, and the product remains activated and signed in (at least for me). However, when you try to sign out (whether you sign out while connected to the internet or sign out while disconnected) it completely deactivates office products.

Then it is working the way Microsoft says it should be working now. 

It has changed; there is no doubt about that. It isn't a change for the better.

You should post feedback, as Rohn007 has already suggested.

Rohn007:

Yeah, I did, hope they'll notice.

Stefan:

You can indeed sign in while connected to the internet, then disconnect from the internet, and the product remains activated and signed in (at least for me). However, when you try to sign out (whether you sign out while connected to the internet or sign out while disconnected) it completely deactivates office products.

Ron Barker:

It's not a similar thread. That thread is on someone opening office app and closing it, then after opening again he / she needs to sign in again. The person doesn't mind being signed in, but their issue is that he / she constantly gets a pop-up after opening an office app while they did not click on sign-out. this is not my situation. After I sign in, i do not get a new pop-up after closing and opening again.

My issue is (to summarize again):

• I have office 365 personal for only 1 device (it's the only device me and my wife use).
• open an office app.
• forced to sign in and can then use all functionality of the office apps while being connected or disconnected from the internet.
• Clicking on 'sign-out' within an office app completely deactivates the app (for example Word), it won't allow you to even type words. It doesn't matter whether I'm connected or disconnected to the internet when signing out.
• there is no other way for me to use Office apps other than signing in and remain signed in at all times (it's not an issue of being connected or disconnected to the internet and since I'm not using any other devices it is also not an issue of multiple devices signing in).

The above points were different for me a month ago where  before I could sign out and still remain using the Office apps, they remained activated (just no online functionality) regardless of being connected or disconnected to the internet. I understand from Rohn007 that this seems to only occur on some machines which leads to the notion that MS is testing something or slowly rolling out this 'feature' of forcing you to remain signed in (for purposes not clear especially when you don't want to use online features).

I guess there is nothing I can do for now, just be at the mercy of MS while they change the way you can use the product midway through the year while I payed for it at the beginning of the year.

As Rohn007 said, for those experiencing the same just hit the feedback from within office apps or add it to the feedback hub. Also upvote here https://word.uservoice.com/forums/304924-word-for-windows-desktop-application/suggestions/40499542-require-option-to-remain-signed-out-of-office-acco

Here is a similar thread from 2018: 

Why do I have to sign in to Office account EVERY time?

Yes, we all have to be signed in (that is a fairly new requirement), but some people suggest that it is possible to be signed in without having an internet connection. I haven't tried if that actually works, though.

Being signed in to Office 365 REQUIRES an internet connection. I have tried.