sorry for my english
help me.thank for all 
Hmm, I never heard about this problem before and have no idea why the installer would pop up this message, which seems inappropriate since you’re evidently trying to install on your C: drive.
If you can’t get the installer to work, you can alternatively download Tiled as 7-zip archive from https://update.mapeditor.org/snapshots-win/. They’re not the releases but the development snapshots, but they are generally just as stable (you could even benefit from a few additional features!).