Steve Smith
Steve Smith
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The Ultimate Guide to Fixing QuickBooks Error 6123

QuickBooks is a powerful tool used by small and medium-sized businesses for accounting and financial management. However, like any software, it can encounter errors that disrupt workflow. One common issue users face is QuickBooks Error 6123. This error typically occurs when opening or upgrading a company file and can stem from various causes. In this guide, we’ll explore the potential causes of Error 6123 and provide a detailed, step-by-step approach to resolving it.

Understanding QuickBooks Error 6123

Error 6123, "Connection to the QuickBooks company file has been lost," usually appears under the following circumstances:

  • Restoring a backup of your company file.
  • Upgrading a company file to a newer version of QuickBooks.
  • Opening a company file over a network.

The error can be triggered by multiple factors, including:

  • Corrupted QuickBooks files.
  • Interference from security software.
  • Network connection issues.
  • Damaged Windows user profiles.
  • Misconfigured firewall settings.

Step-by-Step Guide to Fix QuickBooks Error 6123

Step 1: Update QuickBooks

Before attempting any other fixes, ensure that your QuickBooks software is up-to-date. Outdated software can lead to various errors, including Error 6123. To update QuickBooks:

  1. Open QuickBooks.
  2. Go to Help in the menu bar.
  3. Select Update QuickBooks Desktop.
  4. Click on Update Now and then Get Updates.
  5. Restart QuickBooks after the update completes.

Step 2: Rename the .ND and .TLG Files

The .ND and .TLG files are configuration files that allow QuickBooks to access a company file in a network or multi-user environment. Renaming these files can help resolve the issue:

  1. Open the folder where your company file is saved.
  2. Locate files with the same name as your company file but with .ND and .TLG extensions (e.g., MyCompanyFile.qbw.ND and MyCompanyFile.qbw.TLG).
  3. Right-click on each file and select Rename.
  4. Add the word .old at the end of each file name (e.g., MyCompanyFile.qbw.ND.old).
  5. Reopen QuickBooks and try to open your company file.

Step 3: Use QuickBooks File Doctor

QuickBooks File Doctor is a tool designed to fix various QuickBooks errors, including Error 6123.

  1. Download and install the QuickBooks Tool Hub from the official Intuit website.
  2. Open the QuickBooks Tool Hub.
  3. Select Company File Issues from the menu.
  4. Click on Run QuickBooks File Doctor.
  5. In QuickBooks File Doctor, select your company file from the drop-down menu. If you don't see your file, browse to locate it.
  6. Choose Check your file and then Continue.
  7. Enter your QuickBooks admin password and click Next.

QuickBooks File Doctor will scan and repair your company file. This process may take some time, depending on the file size.

Step 4: Disable Antivirus and Firewall Temporarily

Sometimes, security software can interfere with QuickBooks. Temporarily disabling your antivirus and firewall can help determine if they are causing the issue:

  1. Disable your antivirus software by right-clicking on the antivirus icon in the system tray and selecting Disable or Turn off.
  2. Turn off your firewall through the Control Panel:
  • Open Control Panel.
  • Go to System and Security.
  • Select Windows Defender Firewall.
  • Click on Turn Windows Defender Firewall on or off.
  • Turn off the firewall for both private and public networks.

After disabling these security features, try opening your QuickBooks company file again. If the error is resolved, consider adding exceptions in your antivirus and firewall settings for QuickBooks.

Step 5: Create a New Windows User

A corrupted Windows user profile can also lead to Error 6123. Creating a new Windows user account can help resolve the issue:

  1. Open Control Panel and go to User Accounts.
  2. Select Manage another account and then Add a new user in PC settings.
  3. Follow the prompts to create a new user account with administrative rights.
  4. Log out of your current user account and log in to the new account.
  5. Open QuickBooks and try accessing your company file.

Step 6: Move the Company File to a Different Location

Sometimes, the location of your company file can cause Error 6123. Moving the file to a different folder can help:

  1. Close QuickBooks.
  2. Navigate to the folder where your company file is currently stored.
  3. Copy the company file (with the .qbw extension) and paste it into a new folder or directly onto your desktop.
  4. Open QuickBooks and go to File > Open or Restore Company.
  5. Select Open a company file and navigate to the new location of the company file.

Step 7: Reinstall QuickBooks

If none of the above steps work, reinstalling QuickBooks may resolve the issue:

  1. Open Control Panel and go to Programs and Features.
  2. Find QuickBooks in the list, right-click it, and select Uninstall.
  3. Follow the prompts to uninstall QuickBooks completely.
  4. Download the latest version of QuickBooks from the official Intuit website.
  5. Install QuickBooks and try opening your company file.

Accounting & Bookkeeping Services For Your Business can also help manage and prevent such errors by maintaining your financial records accurately and efficiently.


QuickBooks Error Code 6123 can be a frustrating roadblock, but with the right approach, it can be resolved efficiently. By following the steps outlined in this guide, you can address the root causes of the error and get back to managing your finances without interruption. Remember, keeping your software updated and regularly backing up your company files can prevent many common QuickBooks issues. If you continue to experience problems, consider reaching out to QuickBooks support for further assistance.

Read more - QuickBooks Error - QuickBooks Error Codes List And Its Easy Solution To Fix Guide

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