Error 3734

https://support.microsoft.com/en-us/kb/274211
Too many active users https://msdn.microsoft.com/en-us/library/bb178253(v=office.12).aspx

Error: The database has been placed in a state by user 'admin' on machine 'ADMIN'
that prevent it from being opened or locked

https://social.msdn.microsoft.com/Forums/en-US/7a4ac312-c76d-4043-a1e6-6ce775b583ae/the-database-has-been-placed-in-a-state-by-user-admin-on-machine-admin-that-prevent-it-from?forum=accessdev
"... the error message seems to be triggered, if your Access database is opened and closed repeatedly,
which is not recommended. Is it possible to make your changes by accessing your database only once?
The kb-article to your error message can be found at [1].
   [1] http://support.microsoft.com/kb/274211/en-us