The transaction log file (.TLG) logs all changes to the company file before they are written to the file by the database manager. The transaction log file is named [company file name].qbw.tlg.
You cannot open the .TLG file, nor can you convert it into a company data file (.QBW).
The .TLG file is stored in the same folder as the QuickBooks company file (.QBW file) and should be kept there at all times. If you move or copy the .QBW file to another folder, copy or move the .TLG file with it.
If your data file loses connection to the .TLG file, QuickBooks will automatically create a new .TLG file. If part of a transaction was recorded to the company file but the whole transaction is present in the .TLG file, the transaction will be completed the next time the file is opened in QuickBooks.
If you need to restore an old backup of your company file, you can use QuickBooks Automatic Data Recovery to try to take the changes in the .TLG file (everything since the last successful backup) and enter them into the data file. When this is necessary, it is important that the .TLG file, and the most recent backup are preserved.
The .TLG file can be very large, much larger than the company file. Large .TLG files can have adverse effects on QuickBooks' performance.
QuickBooks will reset the .TLG file if: