Steam version.
No changes or addons.
The problem:
After adding a NVME to my pc, the simulator won’t load (It is stuck at blue loading bar with black background).
The sim is installed on D:/ drive and Windows 11 it’s installed on C:/ drive.
Before replacing the C drive, the sim worked perfectly.
I’ve tried -FastLaunch option at steam parameters and tried removing some registry variables that someone recommended in this forum.
Any help would be appreciated. Ty!!
The sim is always installed on the C: (or boot) drive by the MS/Asobo download program (MS Store or Steam).
Did you “Clone” your C: drive?
If not, FS2020 will not know where its programs are.
If your C: drive and Window 10 is okay:
Go to Settings, Apps and under MS Flight Simulator, click “Uninstall”.
Go to MS Store or Steam and install FS2020 again.
if you have the “Installed Packages” on your D: drive, those files will not be downloaded again.
And only the 1.xx GB will download to your C: drive.
If the download pgm can’t find the “Installed Packages”, it will download them again.
Here are the steps I used to do the same thing and it worked like a charm.
After moving, start FS. It will prompt you to download because it’s still pointed to your c drive. Update the path to your new path where you moved the game and it should work.
Hi! Flight Simulator won’t appear when I go to Settings → Apps, however I’ve deleted it from Steam and it downloaded the 1.xx “launcher”. Then, when I started the game it downloaded 400MB or so, went to the loading page and got stuck again
Hi, thanks for your reply. I’ve done this but by uninstalling and reinstalling the MSFS launcher from steam (the 1.xx Gb launcher), and it keeps freezing at loading screen (The screen which says something like “New Activities” with a blue loading bar)
Okay update here, I uninstalled and installed again the game from steam, but I never have deleted the Packages folder (Where Community and Official folders are). This was the second time I deleted the game from steam but this time when starting the game instead of selecting the same folder of installation (the above mentioned) I selected another one, said it had to download the full game and then I selected back the initial folder where the game was already downloaded. This made the game download 400Mb or so, and once downloaded it started normally and went to the main menu without any problems.
Thank you @SkyWarrior7407 and @MSFSRonS for your replies! Now back to sky! 
Closed as a Solution was found.