Oh, the sync button. Why didn't you mention that earlier. I think you have reinvented the wheel.
I have not seen that problem in a long time.
The somewhat glib response points to a glaring issue with BIAB..."old hands" find & share solutions and the program isn't modified to resolve them as there's insufficient "call" to do so.
Newer users are left with the task of problem identification & solution finding or asking for help in the forum as the search engine for such issues is, at best, hopeless.
If the wheel isn't known it will, eventually, be (re)invented.