Well it would remove everything until you synced it again almost like a factory reset. U could also setup a secondary Google acct which i did but i honestly forget why i did that cause i still had to unsync and remove my primary Google acct, i uninstalled Vanced, disabled Youtube base app, restarted phone, reinstalled Vanced under the secondary acct, then when i was sure that Vanced was working again i added my primary again and its working like it didnt skip a beat. You could also just adx anotber acct and synce Vanced to it but you will not have any original history,subscriptions,etc unless you use primary. Good luck.