If you're having this problem and this still doesn't fix it, try running it as an administrator:
1) Go to (your user folder)\AppData\Roaming\itch\apps\Rusty Lake Roots OR "Show Local Files" in the app
2) Right click RustyLakeRoots.exe, select properties
3) Go to the compatibility tab, check "Run as an administrator" and apply
I got an error when I tried to launch it from the Itch app (think this might be a bug with the app), but had no problem launching it from a shortcut.