yet another file locking bug: must close prefs.db before moving

aqt/profiles.py

@@ -231,6 +231,11 @@ and no other programs are accessing your profile folders, then try again."""))
         new = not os.path.exists(path)
         def recover():
             # if we can't load profile, start with a new one
+            if self.db:
+                try:
+                    self.db.close()
+                except:
+                    pass
             broken = path+".broken"
             if os.path.exists(broken):
                 os.unlink(broken)