How to Fix QuickBooks Error 6073 99001: Unable to Open Company File

QuickBooks is a powerful accounting software widely used by small and medium-sized businesses. However, like any other application, it’s not immune to occasional technical issues. One of the common problems users face is QuickBooks Error 6073 99001, which usually occurs when trying to open a company file. This error message often reads:

“QuickBooks is unable to open this company file. It may have been opened by another user.”

If you’re encountering this issue, don’t panic. This guide will walk you through what causes the error and how to resolve it step by step.

What Is QuickBooks Error 6073 99001?

QuickBooks Error 6073 99001 typically appears when QuickBooks is unable to access the company file due to incorrect file permissions or network issues. It is most common in multi-user environments where the company file is stored on a server and accessed by multiple users.

Common Causes of Error 6073 99001

Understanding the root cause is essential for proper troubleshooting. Here are some common reasons why this error may occur:

1. The file is already open in Single-User Mode on another computer.
   
   

2. The company file is located on a read-only network folder.
   
   

3. The file is being accessed remotely using a Remote Desktop or LogMeIn session.
   
   

4. File permissions on the server are incorrect.
   
   

5. Network issues or conflicts with the .ND (Network Data) file.

Signs and Symptoms

• QuickBooks suddenly crashes or freezes when opening a company file.
  
  

• You receive an error message stating QuickBooks can’t open the company file.
  
  

• The software becomes unresponsive in a multi-user setup.
  
  

• Users are locked out of the file despite having the correct credentials.
  
  

Step-by-Step Guide to Fix QuickBooks Error 6073 99001

Step 1: Check If the File Is Open in Single-User Mode

If the company file is open in Single-User Mode on another workstation, only that user can access it. To fix this:

• Ask the user currently using the file to switch to Multi-User Mode:
  
  

  • Go to File > Switch to Multi-User Mode.
    
    

• Close and reopen QuickBooks on your computer to see if the error is resolved.
  
  

Step 2: Use QuickBooks File Doctor

QuickBooks File Doctor is a built-in tool designed to automatically detect and repair company file and network issues.

• Download and install the QuickBooks Tool Hub from the official Intuit website.
  
  

• Open the Tool Hub and click on Company File Issues.
  
  

• Select Run QuickBooks File Doctor.
  
  

• Browse and select your company file.
  
  

• Click Check your file and enter your QuickBooks admin password.
  
  

• Let the tool complete the scan and attempt repairs.
  
  

Step 3: Verify Folder Permissions on the Server

If the company file is stored on a network drive, you need to ensure that users have full access:

• Navigate to the shared folder on the host computer.
  
  

• Right-click the folder > Properties > Sharing > Advanced Sharing.
  
  

• Make sure “Share this folder” is checked and Permissions are set to Full Control.
  
  

• Also check Security tab and make sure all QuickBooks users have full permissions.
  
  

Step 4: Check for Read-Only Attributes

Sometimes the file or its folder might be marked as read-only, preventing QuickBooks from writing to the file.

• Locate the company file (.QBW) on the server.
  
  

• Right-click > Properties.
  
  

• Uncheck the Read-only box if it’s selected.
  
  

• Click Apply and then OK.
  
  

Step 5: Rename the .ND and .TLG Files

The .ND and .TLG files help QuickBooks access a company file in a network or multi-user setup. If they’re damaged, they can trigger error 6073.

• Go to the folder where your company file is stored.
  
  

• Look for files with the same name as your company file but with .ND and .TLG extensions.
  
  

  • Example: companyfile.qbw.nd and companyfile.qbw.tlg
    
    

• Right-click and rename both files by adding .old at the end:
  
  

  • companyfile.qbw.nd.old
    
    

  • companyfile.qbw.tlg.old
    
    

• Open QuickBooks again and try accessing the file. QuickBooks will auto-create fresh .ND and .TLG files.
  
  

Step 6: Disable Remote Access Software (if applicable)

If you or another user is accessing the company file via remote access tools like LogMeIn, Remote Desktop, or TeamViewer, these tools may lock the file and trigger the error.

• End any active remote sessions.
  
  

• Try opening the company file directly from the server or mapped drive.
  
  

Preventing Future Occurrences

To avoid seeing Error 6073 99001 again in the future, follow these best practices:

• Always use Multi-User Mode in shared environments.
  
  

• Ensure all users exit QuickBooks before updates or server maintenance.
  
  

• Regularly back up your company file to prevent data loss.
  
  

• Keep QuickBooks Desktop and Windows OS up to date.
  
  

• Train staff on proper file-sharing protocols.
  
  

Conclusion

QuickBooks Error 6073 99001 can be frustrating, but it’s usually easy to fix with the right steps. By understanding the causes—whether it's file mode conflicts, permission issues, or network errors—you can quickly regain access to your company file and resume your accounting tasks. If none of the steps above resolve the issue, it may be time to consult a QuickBooks ProAdvisor or Intuit support for more advanced troubleshooting.

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