Currently I am working on a project which uses Access Database. Anyway, so I designed, populated and uploaded the database to the server and it was giving me the error that "File is already being used". I was confused since the database file was not being used by any other process. Finally, I realized that error comes when you forget to close the connection. I find it really strange because it never gave me error when running on local server.
It's a very bad practice to keep the connection open for a long time. I guess some production servers requires the server to be closed in order for successful processing. So, always always always always close the database connection after using it.