You can “trick” MSFS into doing forced download. This will also verify existing files. Remove all mods from the Community Folder.
Step 1: Close Microsoft Flight Simulator and navigate to the UserCfg.opt file that you can find at the following location by default: C:\Users\YourUsername\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache
Step 2: Create a new folder. For instance “Package 2”
Step 3: Open the UserCFG.opt file with Notepad, scroll down to the bottom of the page, and change the following line to point to the new folder: InstalledPackagesPath “C:\Users\YourUsername\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\Packages 2”
Step 4: Relaunch the Microsoft Flight Simulator
Step 5: Sign in with the the Microsoft account used to purchase Microsoft Flight Simulator
Step 6: The update screen should now be available again
Step 7: Make sure that the installation path points to the original/correct installation folder (in this case “packages” and not packages 2" for instance)