This indicates that someone has your file open.
Either the individual's PC has Access open as an active file or as a background process OR someone didn't close the file properly, this can happen when the sever drops the connection or if the user simply turns their PC off via a hard power down.
1)
ABSOLUTLY make a backup of your file using either the OS and simply making a copy of the file to another location or via your favorite backup software.
2) Since you are in the directory where the database resides, you will find a file with the same name as your database with the extension "ldb" - read here before you do anything:
Introduction to .ldb files
3) Make sure everyone has Logged out of their accounts. Ideally they would actually power off their PC.
4) Now REBOOT the server/PC where the file resides. This ensures that no-one has the file open on their client. DO NOT ALLOW ANYONE TO OPEN THE DATABASE AT THIS POINT!
5) Rename the .ldb file:
From: yourdatabasename.ldb
to: old_yourdatabasename.ldb
6) Attempt to re-open your database.
6a) if you can open this database I highly advise that you move your database by the following steps:
- create a new, blank ACC2010 database.
- using the external data tool, open your old database for IMPORT and import all of the tables, queries, forms, reports, macros, and VBA modules into the new database.
- Save this database in the ACC2007/2010 format.
Keep in mind that as of ACC2013 any and all access files prior to ACC2003 are depreciated and will not be accessible starting with ACC2013 unless you use ACC2010 or OLDER.