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How to Fix QuickBooks Error 6123 0?

Mar 24, 2025 | Uncategorized

QuickBooks Error 6123 0 is a common issue that stops you from opening, backing up, or restoring your company file in QuickBooks Desktop. You might see a message like “Error 6123 0: Connection to the QuickBooks company file has been lost.” This error can happen in single-user or multi-user mode, often because of network problems or damaged files. No need to panic! This guide explains why this error happens and gives easy steps to fix it. We use simple words and clear instructions to help you solve the problem quickly.

Why Does QuickBooks Error 6123 0 Happen?

Error 6123 0 can occur for these reasons:

  • The company file or its related files (.ND or .TLG) are damaged.
  • Network connection issues block QuickBooks from accessing the file.
  • Antivirus or firewall settings interfere with QuickBooks.
  • QuickBooks Database Server Manager is not running.
  • The company file is on a network drive with an unstable connection.
  • QuickBooks is outdated or has corrupted installation files.

Understanding the cause helps you pick the right solution. Below, we share step-by-step methods to fix QuickBooks Error 6123 0.

Solution 1: Rename the Company File and ND/TLG Files

Damaged company files or their network data (.ND) and transaction log (.TLG) files can cause Error 6123 0. Renaming them allows QuickBooks to create fresh versions.

  1. Open the folder where your company file is stored (usually in C:\QuickBooks or a network drive).
  2. Find the file with the .qbw extension (e.g., company.qbw).
  3. Right-click it and choose Rename. Add “_old” to the name (e.g., company_old.qbw).
  4. Look for .ND and .TLG files with the same name (e.g., company.qbw.ND, company.qbw.TLG).
  5. Rename them by adding “_old” (e.g., company.qbw.ND_old, company.qbw.TLG_old).
  6. Open QuickBooks and try accessing the company file.

If the error remains, move to the next solution. For more help with company file issues, check our guide on QuickBooks Company File Not Found.

Solution 2: Use QuickBooks File Doctor to fix QuickBooks Error 6123 0

QuickBooks File Doctor, part of the QuickBooks Tool Hub, can diagnose and fix company file errors like 6123 0.

  1. Download the QuickBooks Tool Hub from the official Intuit website.
  2. Save the file, double-click to install, and open the Tool Hub.
  3. Go to Company File Issues and click Run QuickBooks File Doctor.
  4. Select your company file from the list or browse to find it.
  5. Choose Check File Damage Only, then click Diagnose File.
  6. Enter your admin password if prompted, then follow the prompts to repair.
  7. Open QuickBooks and check if the error is fixed.

For detailed steps, see our post on QuickBooks File Doctor.

Solution 3: Restart QuickBooks Database Server Manager

The QuickBooks Database Server Manager (QBDBMgrN) helps QuickBooks access company files in multi-user mode. If it’s not running, Error 6123 0 can appear.

  1. Press Windows + R to open the Run window.
  2. Type services.msc and press Enter.
  3. Find QuickBooksDBXX (XX matches your QuickBooks version, e.g., QuickBooksDB30 for 2020).
  4. Right-click it and select Start or Restart.
  5. If it’s already running, right-click and choose Stop, then Start again.
  6. Open QuickBooks and try opening the company file.

If this doesn’t work, read our guides on QuickBooks Database Server Manager and QBDBMgrN Not Running on This Computer.

Solution 4: Move the Company File to a Local Drive

A company file on a network drive with a weak connection can trigger Error 6123 0. Moving it to a local drive can help.

  1. Open the folder where your company file is saved.
  2. Copy the .qbw file (e.g., company.qbw).
  3. Paste it to a local drive, like C:\QuickBooks.
  4. Open QuickBooks and go to File > Open or Restore Company.
  5. Select the file from the local drive and open it.
  6. Check if the error is gone.

For network-related issues, see our post on QuickBooks Error H202.

Solution 5: Disable Antivirus or Firewall Temporarily

Antivirus or firewall software can block QuickBooks, causing Error 6123 0.

  1. Open your antivirus or firewall program.
  2. Look for an option to disable it temporarily.
  3. Turn off the antivirus or firewall.
  4. Open QuickBooks and try accessing the company file.
  5. Turn the antivirus or firewall back on after testing.

To configure firewall settings properly, check our guide on Configure Firewall for Multi-User Mode in QuickBooks.

Solution 6: Run QuickBooks as Administrator

Running QuickBooks with admin rights can fix permission issues linked to Error 6123 0.

  1. Close QuickBooks if it’s open.
  2. Right-click the QuickBooks icon on your desktop.
  3. Select Run as Administrator.
  4. Try opening your company file again.

If the error persists, try the next solution. For similar issues, read our post on QuickBooks Unable to Open Company File.

Solution 7: Repair QuickBooks Installation to Fix QuickBooks Error 6123 0

Corrupted QuickBooks files can cause Error 6123 0. Repairing the installation may fix the issue.

  1. Close QuickBooks.
  2. Press Windows + R, type appwiz.cpl, and press Enter.
  3. Find QuickBooks in the list, click it, and select Uninstall/Change.
  4. Choose Repair and follow the instructions.
  5. Restart your computer and open QuickBooks.

For detailed repair steps, see our guide on Repair QuickBooks Desktop for Windows.

Solution 8: Create a New Windows User

A corrupted Windows user profile can cause Error 6123 0. Creating a new user can help.

  1. Press Windows + I to open Settings.
  2. Go to Accounts > Family & other users.
  3. Click Add someone else to this PC.
  4. Follow the prompts to create a new user with admin rights.
  5. Log in to the new user account and open QuickBooks.
  6. Try accessing the company file.

If this works, you may need to repair your old user profile. For other error fixes, check our post on Fix Common QuickBooks Enterprise Errors.

Solution 9: Restore a Backup File

If the company file is too damaged, restoring a backup can fix Error 6123 0.

  1. Open QuickBooks and go to File > Open or Restore Company.
  2. Select Restore a Backup Copy and click Next.
  3. Choose Local Backup and find your backup file (.qbb).
  4. Follow the prompts to restore the file.
  5. Open the restored file and check if the error is fixed.

Learn more about backups in our guide on Restore a Backup of Your QuickBooks Company File.

Solution 10: Update QuickBooks to the Latest Version

An outdated QuickBooks version can cause errors like 6123 0. Updating it may solve the problem.

  1. Open QuickBooks Desktop.
  2. Go to Help > Update QuickBooks Desktop.
  3. Click Update Now and select Get Updates.
  4. Wait for the download to finish, then restart QuickBooks.
  5. Follow prompts to install the updates.

For update issues, see our posts on QuickBooks Desktop Update Errors and Update QuickBooks to Latest Release.

Solution 11: Check Network Connection to Fix QuickBooks Error 6123 0

A weak network can cause Error 6123 0, especially in multi-user mode.

  1. Ensure all computers on the network are connected.
  2. Ping the server:
    • Press Windows + R, type cmd, and press Enter.
    • Type ping [server name] and press Enter.
    • If you see “Request timed out,” contact your network admin.
  3. Try opening the company file from a local drive.

For multi-user issues, check our guide on QuickBooks Multi-User Mode Not Working Error.

Additional Tips to Prevent QuickBooks Error 6123 0

To avoid this error in the future:

  • Update QuickBooks and Windows regularly to avoid compatibility issues.
  • Store your company file on a local drive for faster access.
  • Use a stable network for multi-user mode to prevent connection issues.
  • Back up your company file often to protect your data. Learn how in our guide on QuickBooks Auto Data Recovery.
  • Run regular maintenance on your QuickBooks files to detect issues early. See our post on Rebuild QuickBooks Data File.

Conclusion

QuickBooks Error 6123 0 can disrupt your work, but these 11 solutions can help you fix it. Start by renaming files, using QuickBooks File Doctor, or restarting the Database Server Manager. If needed, restore a backup or update QuickBooks. Our guides at Transyncpro.com, such as QuickBooks Tool Hub, QuickBooks Error H202, QuickBooks Database Server Manager, and QuickBooks File Doctor, provide more help. If the error does not go away, contact our support team. Get back to using QuickBooks smoothly with these easy steps!