compatibility

Yes many are using it.

Have FSX Gold, Deluxe, Accel Exp Pack which has failed multiple installation attempts. During process offers Repair or Remove neither of which work since FSX was uninstalled prior to W7 to W10 migration. MSKB928080 does not appear available to reset licence if this is the problem. MS and other suggestions tried without success. Assume something left over from uninstall prior to W7 to W10 migration. Need a flyaway magic wand.

Your right.
Something is left from the old install.
Usually it's in the registry or a hidden folder.

Try this and see if it does the job.

http://www.revouninstaller.com/revo_uninstaller_free_download.html