QuickBooks Desktop 2018 Company File Types: What to Protect
QuickBooks Desktop 2018 creates several file types. Learn what .QBW, .QBB, .QBM, .ND, and .TLG files do and which ones to back up for long-term use.
QuickBooks Desktop 2018 officially reached end-of-life on May 31, 2021. While Intuit no longer provides updates, banking connections, or live support for this version, the software itself continues to function offline. If you are keeping your 2018 installation alive for the long haul, understanding the files it generates—and knowing exactly which ones to protect—is the foundation of your data safety strategy.
The Files QuickBooks Desktop 2018 Creates
When you set up and run a company in QuickBooks Desktop 2018, the software generates several distinct files and folders. The behavior and structure of these files are identical across recent Desktop versions (Pro, Premier, and Enterprise). Here is what each file does:
- .QBW (QuickBooks Company File): This is your primary, live working file. Every transaction, customer profile, and report setting lives here. It is the file you open day-to-day.
- .QBB (QuickBooks Backup): This is a compressed archive of your company file. QuickBooks creates this when you use the built-in backup utility. It is highly compressed and serves as your primary safety net.
- .QBM (QuickBooks Portable File): A highly condensed version of your company file designed specifically for easy transfer—such as emailing it to an accountant or moving it between a desktop and a laptop. It is smaller than a .QBB but lacks some temporary data.
- .ND (Network Data File): A small configuration file that allows QuickBooks to communicate across a local network in multi-user mode. If this file is missing or damaged, QuickBooks will often fail to open the company file in multi-user mode.
- .TLG (Transaction Log File): This file tracks every change made to your company file since your last backup. It is essential for the automated backup and recovery process, allowing QuickBooks to restore data right up to the moment of a crash or power failure.
Which Files to Protect for the Long Haul
Because QuickBooks Desktop 2018 is a discontinued product, you cannot rely on Intuit to help reconstruct a damaged or lost company file. Your internal backup strategy is your only safety net.
For long-term preservation, you must prioritize the following:
- The .QBB (Backup File): This is your most critical asset. A valid .QBB contains everything needed to restore your books to a new installation of QuickBooks Desktop. You should generate a new .QBB at the end of every working session.
- The .QBW (Working File): You should always keep a copy of your live .QBW file, but never move or copy it while QuickBooks is running, as this can cause corruption.
- The .TLG (Transaction Log): Always keep your .TLG file in the same folder as your .QBW file. If your .QBW ever fails, the .TLG file works in tandem with your most recent .QBB backup to recover any data entered since that backup was made.
You do not need to back up the .ND file. If it is lost or corrupted, QuickBooks Desktop 2018 will automatically recreate it when you open the company file or run the QuickBooks Database Server Manager.
Safe Handling Practices for Unsupported Versions
Because you are operating without Intuit's safety net, how you store these files matters as much as generating them.
Never store your only copy of a .QBB or .QBW on the same physical drive as your operating system. If the hard drive fails, both your live data and your local backup will be lost. Maintain at least two copies of your .QBB file: one locally (on an external USB drive or network attached storage) and one off-site (such as a secure cloud storage provider).
If you ever need to move your accounting data to a new computer, always move the .QBB file, open it inside the QuickBooks Desktop 2018 installation on the new machine, and let the software rebuild the live .QBW and .ND files from that backup.
Finally, if your live .QBW file begins throwing verification errors or refuses to open, stop using the automated Rebuild utility immediately if it fails on the first attempt. Running it repeatedly on a severely damaged file can overwrite the very data you are trying to save. At that point, your best next step is to safely extract the data from your most recent clean backup.