There was a new patch today and again i'm getting the error i mentioned, this time the fix (deleting osu!.exe and running the updater) Doesn't work. and i keep getting the same error.
Hmm, i tried deleting the osu!.exe and ran the updater a couple of times more and eventually it worked anyway. Still a weird problem and very consistent it seems.
Something on your PC is changing permissions. This is the only way this can happen. You can try resetting permissions from the maintenance section in options.