Part of your QuickBooks company data is the TLG file. It’s not something you normally are aware of, but in some situations it can be a very important file.

The transaction log file (TLG for short) is maintained automatically by QuickBooks as part of your data. The file resides in the same folder as your main QBW file, and has the same file name. But it has a .TLG extension. In transaction-intensive businesses, the file can become quite large — 1GB or bigger.

Whenever you post a transaction in your company file, the TLG file is updated. And that is why it is sometimes a very valuable file.

We sometimes talk to people who have lost their current data file — it either got deleted somehow, or is so badly damaged it is unusable and unfixable.

But if they have a good backup — even if it is old — and a good current TLG file, we can take the old backup and bring it to current status by applying the missing transactions we can get out of the TLG file.

It’s one method we use for QuickBooks data repair.

I am working with a customer today who has this exact scenario, so I thought I’d briefly write about it.

p.s. We occasionally hear of users being instructed to delete their TLG file. Don’t ever do that without copying it to a different folder or drive first. You might need it sometime!