Great it worked for me. MS Store version and a good alternative when we loose the servers, either as a result of MS server issues or one of our own network lost issues.
Thanks for the tip,
Feb 18 2021 Update: It worked first time for me only. I setup Offline in the Store. When i startup MSFS when should I see the “choice” to run offline?
I wasn’t aware of that. Thank you.
When does soft warning appear? Before Checking updates I assume, but where before?
I believe it was before checking updates, yes. May have only been on my computer?
I am having an issue with the “Your game license could not be Authenticated” and it seems like I am not playing online. Has anyone had this issue and is there a fix? I can login to the Microsoft store and I know I have internet connectivity because I uninstalled and re-installed the digital downloaded and it loaded properly. I’m at a loss.
Thank you, I was not aware of this. Useful thing to turn on!
I wish for this feature as well. I use to work on cruise ships as an entertainer and though I doubt I’ll be doing that anytime soon, the one thing I loved was being able to fly flight simulator. While they do have internet at seas it is costly just to sign in so I can use the simulator.
Turn on the offline mode before you leave shore! I assume you’re using your own laptop, so you could do it at home and then play anywhere.
Till you get a CTD 
The core world is there. Ai generated base scenery is there too. If you disconnect from the servers and fly offline, it is similar to flying in FSX. Heightmaps and such are inaccurate and details are non existent but you CAN fly anywhere you want. IF you fly in a cached area then you would not notice any significant difference.
I am sure the piracy concerns MS/Asobo indicated is really the driving force behind requiring online verification before allowing any functionality. ■■■■■■, but when you look at the billions lost every year to unlicensed software, understandable.
Yeah but offline mode doesn’t work. I just tried it, and it’s asking me for the Game Disc. Oh well.
By sheer coincidence, I turned on offline mode earlier today. I followed this guide - Xbox Support
Then, I logged on and loaded up a flight, and then exited the game in the normal way. Everything seemed ok.
However, I just tried playing in offline mode thanks to the Xbox Outage. I removed the ethernet cable from my desktop and rebooted without any network connection. I expected the game to start in offline mode as was stated in the official docs.
Nope. It loads and asks for the game disc. So offline mode does not, in fact, work.
Just an FYI for people
OK I guess we’re not supposed to talk about this or something? My post got moved and buried to the bottom of a long thread.
Time to fly out, methinks.
Could have more to do with the fact that there have been numerous posts/threads today and they have been merged. You are not buried. You are the most recent post in this thread, well second most recent now. 
It has worked for other people, so I’m not sure what is going wrong for you.
In offline mode you don’t get the photogrammetry or bing data I don’t believe (maybe you do if it’s cached and you’re flying in the same area?).
But it doesn’t sound like that’s your problem.
Well since this outage issue also has a “workaround” (ugh another workaround 
), I guess the outage issue is not an issue at all.
Here is to more outages, and many more to come since its no big deal. 
Tried offline mode it is not working for me, I am doing something wronog…either way, funny how they say everything is fixed and yet when I just now try to start the sim it is stuck on the xbox account box…
That doesn’t work for me… Had that setup for a long time on my 2nd low spec system but every time I try to launch offline it asks me to insert disc #1 and it’s a MS Store system.
I fully support the OP’s thoughts because we’ve been without internet connection here for over a week not so long ago.
I wasn’t aware of that. Thanks for enlightening me. 
So why can’t we interact with anybody else in this online world?