Okay… This took a little detective work. When you use a custom font in a win32 build and exit the program the TTF font stays active so you can’t delete the directory or rebuild into that same directory.
Reproduced on Win8 and Win10…
Here’s a link to a build of our LD Jam game to see it happen… Be forewarned you will have to reboot to remove it
http://ponywolf.com/ld33/1-800-monsters-win.zip
I can add this to a proper bug report, but I couldn’t find the link