When I changed my “drive” to a “new drive” (SSD to NvME), I FIRST made a complete and verified “Backup” of my original working OS/Flight Sim Disk. I used professional backup software to create that backup. A boot system drive copy/copy is never recommended and usually never works. After the backup was completed. I removed the original “drive”, put in the new “drive” and restored my backup to my new NvMe drive using my backup software. Removing the original prevents 2 copies of the same software to attempt to boot, always leads to trouble. I verified that all was working and ok, which it was. I was then free to move around my FS if needed and I also had a nice recoverable backup in event everything turned to mush.