Have you noticed when you open an Access database that it generates another (same named) file but with a locking file extension of either an LDB (Microsoft Access 2003 or earlier) or LACCDB (Microsoft Access 2007 or later)?

This file should automatically generate and extinguish itself when opening and closing your Access database and the upshot is that you do not need to do anything with it unless you want to.

What is and Why have a locking file?

First of all it's a safe and harmless file which rides along with your opened database file in the same location and is not a virus (as one IT trainer once tried to impress and proudly inform me!).

It's used to keep track of one or more users who are currently working on the same database and therefore plays the role of keeping a log of multiple users with their machine name and user name.

You can view this file in a plain text editor though some editors might return odd characters (try using Microsoft Word instead of Notepad) and you will see the machine name and user name listed for members currently using the Access database file.

When the last individual closes the shared Access database, it will automatically delete the locking file (well in most cases). However, this doesn't always delete itself and ideally you should physically delete it yourself assuring you of no harm is done.

How do I use it?

I use it in my Access database to view who is currently logged in the database should I need to manage users via different features like sending internal flags and messages to them and that's it really as it will not be a live list of users and update quick enough.

But this file is not created when a user opens the Microsoft Access database file in exclusive mode which means they are the only person who can gain access making this file redundant.