Microsoft Access Issue

Opening an Access database from outside the network requires that the database file be reachable over the network and that Access can create and use its lock file on the shared location.

From the provided information, the relevant points are:

1. When an Access database is on a network file share, Access must be able to create a locking file (*.ldb or *.laccdb) in the same folder as the database. If this cannot be created or used correctly, errors such as:
   • Could not use 'path to database.accdb'; file already in use.
   • Could not lock file can occur.
2. To allow multiple users (including remote users connecting over a network path) to open the database, all users must have Read, Write, and Create permissions on the folder that contains the database file so that the locking file can be created and updated.
3. There is a known issue when opening a database on a network file share (including UNC paths, DFS, mapped drives) that can cause the same errors. This issue has been fixed in specific Office/Access builds. To ensure this fix is applied, Office/Access must be updated to the latest build on all machines that open the database.

Actionable steps based on this:

1. Confirm that the remote machine can reach the database location using a valid network path (for example, a UNC path like \\Server\Share\Folder\Database.accdb).
2. On the file server, ensure the user account used from outside the network has Read, Write, and Create permissions on the folder containing the .accdb/.mdb file so Access can create the .laccdb/.ldb lock file.
3. Make sure all machines that open the database (local and remote) have Office/Access updated to the latest version, as described in the “Install Office updates” guidance in the referenced article. The fix for network-path issues is cumulative, so installing the latest update is sufficient.
4. If errors such as “file already in use” or “could not lock file” still occur, verify that the database is not being opened exclusively by any user and that the network path type (UNC, DFS, mapped drive) is supported by the updated build.

If the database file itself is not accessible from outside the network (for example, due to VPN, firewall, or routing restrictions), those connectivity aspects must be resolved by network/IT configuration so that the file share is reachable before Access can open it.

References:

• "File already in use" error when you try to open an Access database that's located on a server
• Error in Access when opening a database on a network file share