Okay, that’s something at least. If you don’t have it already, I would recommend installing the XBox app from the MS Store. Not the XBox Companion app, as that has been superseded.
If we can get your signed out, then back in again to that app, and if that works, we can dig into why MSFS is not launching.
Thanks I will try that 2moro, I have to go now, sorry.
did you get a message about a “temp profile” ? At least I remember some issues related to that and you can google for it. MSFS related is that problem not, some what goes wrong with your windows ( may be because of some corrupt files in your profile ).
PS: and did you mean a Win11 Update or the Win10->11 Upgrade, just to be sure 
That can certainly be a thing, and not always due to a full disk.
@ExceededBull193 What you would see in “C:\Users” is your profile folder, and a copy of it with “.TEMP” appended, if memory serves.
You may find a reboot fixes this, but if not, it involves changing a key in the registry so that your user account points to the correct folder.
If this was steam we were talking about *(and I know it isnt), all you have to do is start the install from the steam store (ms store for you) and let it install the launcher. Then run the launcher, when the update window pops up, wanting you to install the whole sim all over again, click on it, that will bring up a file box, find where you have the old install, installed, ie where flightsimulator.exe is installed and choose that directory, click okay, the sim will sit and think a few, then should come back and show you the path that you just changed to. You should now notice that the file sizes it wants to download are far smaller or non-existent, if its a smaller size just download what it wants, if the file size is non-existent it should proceed to finish loading the already installed sim.
More then likely when you update the registry values for the sim got wiped, so win doesnt see it installed, but doing the above will install the new launcher, and if everything goes the way it does for steam, it will write the new reg values, and create the proper files in the appdata directories…
Good Luck…
I’m on the latest Windows 11 and have zero issues.
Yes but you missed the part where he said he upgrade to 11 from 10, and that looses stuff in the process even though it remains installed.
Ive done it twice to date and the above is what I had to do to get FS back to working state without doing a complete install. No reason the ms store version should work the same way ;p
Same here.
Same with me too, it runs sweet and did so after upgrading from 10-11 too, no issues at all.
Thank you all for the replies. First time today that I have had a chance to update you all. I contacted Windows support, and I was 2 hours with 3 different agents. They were NOT able to help me, and I at end I was left hanging on for over 15 minutes with no reply, so i closed. I told him that Win 11 would not do a restore point. As he was suggested this. Tried loads of things, all failed. I asked for remote assistance, but he did not want to do this? I tried again trying to start Flightsim from MS Store, and it says MSFS IS installed. Click on Play, then an Update button shows. Then the blue bar goes up to about 90%, then it stops and says ‘error?’ Click on ‘See Details’ box shows ‘Someting Unexpected Happened’ I click on ‘Report this problem’ and nothing happens? The error code is 0x8007139F. So not able to start MSFS. I have re-loaded all my apps and the virus checker. It is not BitDefender that is causing the problem, as the problem was here before I had to re-install BD. And after install I totally disabled BD. I had BD before the Win 11 update, and MSFS was working fine, with no crashes, in 4K Ultra Settings. Windows seems to be running OK, but the Win 11 update removed a lot of stuff including IPACS Aerofly, TrainSimulator, including ALL the folders with saved routes and content! It did leave Sims 4. VERY upset by the loss of the games sims, and apps. You can understand my anger towards Microsoft!!! This happened directly after the Win update!!! FS2020 is still there but can not start it. WHAT DO I DO? Sell my PC? I am sick MS Windows.
For me … have been unable to launch Msfs since it became xbox-games foldered … stuck on launch w/ error #x008070102 (or similar … it IS 102) … tried re-install(s) , everything! … still no luck … waiting for a miracle, now! … is it Win 10? , or Msfs? , or xbox-app/game -services? …
I have just found out that the Win 11 update changed the configuration of the SSDs? The Corsair MP600 Pro SSD that use to be drive: C is mow Drive: E. And the older Samsung that used to E: is now C:. A right mess up on my system!!!
That’s extraordinary. If you go into Disk Management you should be able to change them back to what they should be.
I would delete and reformat hard drives and do a fresh install of windows before I would sell or throw away my computer. I use the steam version of flight sim which seems to have less weird problems from the posts I’ve read here. Anyway, my pc came with windows 10 and I upgraded to 11 awhile back with no problems that I’ve noticed. I get the occasional ctd’s when loading from the world map to the game.
It’s probably the way to go but he needs somebody who knows windows to help him I think.
So if your drive letters are messed try this. Go into usercfg.opt scroll down to the last line of the file where you will see the default path. If it points to the old path say the C: drive and now the sim is on the E: drive, change the c to and e and save the file, then try to relaunch/update?
He needs his drives letters to be correct with OS on C and MSFS on whatever drive that was on. Simply changing a path to get one application running is not a very satisfactory solution.
He said everything else worked just not MSFS.
Yes, but his drive letters have changed so it’s unlikely everything else works properly if that is the case. He certainly does not want his OS on any drive other than C, its standard practice to put the OS on that drive.
You can install Windows on any drive that you want.
Windows does not care what drive it is installed on.