QuickBooks Error -6155: Meaning, Causes, and Desktop Fixes

Fix QuickBooks Desktop error -6155, part of the -6000 company-file family. Learn what causes it and how to resolve read-only or in-use file access blocks.

When you try to open, back up, or restore your company file in QuickBooks Desktop and hit error -6155, it usually means the software cannot establish a proper connection to your data. This code belongs to the broader -6000 series of errors—a family of messages triggered when QuickBooks encounters roadblocks while accessing a company file (.qbw). Fortunately, you can almost always resolve these access blocks locally without needing an active Intuit support subscription or a software upgrade.

What Error -6155 Means in Plain English

The -6155 error specifically indicates that the connection between your QuickBooks application and the company file failed. When QuickBooks tries to open the file, it checks for read/write permissions and network pathways. If the file is flagged as "in use" by another process, marked as read-only, or blocked by your operating system's security settings, QuickBooks cannot lock the file properly and throws this error.

Common Causes

Error -6155 can be triggered by several local environment factors:

• Incorrect folder permissions: The Windows user account running QuickBooks does not have full read/write access to the folder containing the company file.
• Damaged network data files: The .ND (Network Data) or .TLG (Transaction Log) files that help QuickBooks access the file across a network are corrupted or out of sync.
• Read-only attributes: The company file itself, or the folder it resides in, is set to read-only.
• Background interference: Antivirus software, backup utilities, or cloud-syncing apps (like OneDrive or Dropbox) are actively locking the file.
• Database Server Manager issues: The QuickBooks Database Server Manager is not running, or has lost track of the folder where your company file is stored.

How to Fix Error -6155

Follow these steps to restore access to your company file. These fixes are safe for older, unsupported, or discontinued versions of QuickBooks Desktop.

1. Test a Local Copy

First, determine if the issue is with the file or your network.

• Create a new folder directly on your C:\ drive (for example, C:\QBTest).
• Copy your company file (.qbw)—or your backup file (.qbb)—into this new folder.
• Open QuickBooks while holding down the Ctrl key to open the application without loading a file, then use the "Open or restore an existing company file" option to open the file from the C:\QBTest folder.
• If the file opens successfully, your original folder lacks proper permissions, or your network path is broken.

2. Rename .ND and .TLG Files

QuickBooks creates .ND and .TLG configuration files to manage multi-user access. If these become damaged, QuickBooks cannot find your company file. Renaming them forces QuickBooks to rebuild them the next time you open the company file.

• Navigate to the folder containing your company file.
• Locate files with the same name as your company file but ending in .ND and .TLG.
• Right-click the .ND file and select Rename. Add .OLD to the end of the filename (e.g., CompanyFile.qbw.ND.OLD).
• Do the exact same thing for the .TLG file.
• Try opening your company file again. (Note: Do not delete these files, and do not rename the .qbw file itself.)

3. Rescan with Database Server Manager

If you are on a multi-user network, the QuickBooks Database Server Manager needs to recognize the updated file locations.

• Open the Start menu on the server computer (the one hosting the files).
• Search for and open QuickBooks Database Server Manager.
• Go to the Scan Folders tab.
• Select Add Folder and browse to the folder containing your company file.
• Click Scan. Once the scan finishes, close the manager and try accessing the file from your workstation.

4. Run Verify and Rebuild Data Utilities

If the file opens locally but you still experience instability, the company file's structure may be damaged.

• Go to File > Utilities > Verify Data.
• If QuickBooks detects a problem, run File > Utilities > Rebuild Data.
• You may need to run the Rebuild utility multiple times until Verify Data comes back clean.

How to Prevent It from Recurring

To keep your Desktop environment stable, ensure the Windows user logged into the computer has full administrative rights and explicit read/write permissions for the QuickBooks folder. If you store your company file in a cloud-synced folder (like OneDrive), move it to a purely local directory, as active syncing constantly locks and unlocks the file, confusing QuickBooks. Finally, configure your antivirus software to exclude the QuickBooks installation directory and your company file folder from active scanning.

When the Company File Itself is Damaged

If you have copied the file to a local drive, renamed the .ND and .TLG files, and the file still refuses to open—or if the Rebuild Data utility repeatedly fails to fix the error—the company file itself is likely severely corrupted. At this stage, the file's internal structure is broken, and you will need dedicated repair tools to extract and rebuild the data. If you are facing this level of corruption, you can repair damaged QuickBooks company files to recover your financial history without being forced to start over or migrate to a new system.