You can try that, yes. If it gives a problem, then best to do what I mentioned about uninstalling and reinstalling - using MSFS installer to point to another drive.
You don’t have to install the main core files of MSFS on C: - but the “app” part of it should be on C:. If you have enough space on C: - then go for it! 
Question:
Did you setup MS Store to have ALL apps go to a different drive? If so, change that back to the C: drive.
