XRayCat

The above solution no longer works on modern OSX. I fixed this annoying bug last night by: Log out of Skitch Uninstall Skitch Using the finder look through ~/Library and search for "skitch". Delete anything that's related to skitch that shows up in those search results, particularly the Skitch stuff in ~/Library/Containers Send all that stuff to trash and clear your trash I restarted my machine, you may not need to, but I was so annoyed at this bug that I restarted Reinstall Skitch and it'll work 🎉