Sim Stuck Loading on Blue Bar
Asobo have acknowledged this as an official bug with the sim and have provided the following guideance:
"We are currently looking into this issue. In the meantime, if your sim stops loading and the blue bar gets stuck, please try the following workarounds:
Exit out of Microsoft Flight Simulator (Alt+F4) and relaunch the title one or two times
Try running the sim as an Administrator
Here is another workaround:
Check your Roaming directory (e.g. C:\Users\<UserName>\AppData\Roaming\Microsoft Flight Simulator. If you see UserCfg.opt, open it and verify that InstalledPackagesPath is set to a path you wish to install your game. (e.g. “D:\Game\Microsoft Flight Simulator”)
Delete everything else in C:\Users\<UserName>\AppData\Roaming\Microsoft Flight Simulator
Start the game again. It should prompt you to select a storage location. If your UserCfg.opt has the InstalledPackagePath set, then the file path of the directory you specified should appear in the text box.
Press Update. It should transition to a screen where you can actually see what files are being downloaded from the server."
More information: https://www.flightsimulator.com/known-issues/