QuickBooks Error 6123 – Connection Lost While Opening Company File

QuickBooks Error 6123 occurs when users try to open a company file, restore a backup, or access data over a network and suddenly see the message “Connection Lost”. This error commonly appears in multi-user mode, hosted environments, or when the company file is stored on a server.

If not fixed on time, QuickBooks Error 6123 connection lost can prevent access to important accounting data and disrupt business operations.

What Is QuickBooks Error 6123?

Error 6123 in QuickBooks is a company file error related to network, permission, or database connectivity issues. It usually happens when QuickBooks is unable to establish a stable connection with the QuickBooks Database Server Manager or the hosted company file.

This error may appear in:

• QuickBooks Desktop

• QuickBooks in multi-user mode

• QuickBooks hosted or cloud environments

Common Causes of QuickBooks Error 6123

Understanding the root cause helps in faster troubleshooting:

• Opening the QuickBooks company file over a network

• Incorrect folder permissions on the server

• Damaged or corrupted company file

• Firewall or antivirus blocking QuickBooks

• Database Server Manager not running

• Restoring a backup file from another system

• Network interruption or unstable connection

• Using outdated QuickBooks version

Symptoms of Error 6123 Connection Lost

You may experience the following issues:

• QuickBooks unable to open company file

• Connection lost while opening company file

• QuickBooks crashes while accessing data

• Error 6123 appears repeatedly

• Slow or frozen QuickBooks performance

• Users disconnected in multi-user mode

How to Fix QuickBooks Error 6123 (Troubleshooting Steps)

1. Verify Network Connectivity

Ensure your system has a stable internet or local network connection, especially when accessing files in multi-user mode.

2. Check Folder Permissions

Make sure the QuickBooks company file folder has full read/write permissions for all users and the server.

3. Restart QuickBooks Database Server Manager

Restarting the database service can fix QuickBooks database connection errors causing Error 6123.

4. Disable Firewall or Antivirus Temporarily

Security software may block QuickBooks communication, resulting in a network connection lost error.

5. Restore Company File Locally

Try restoring the backup file to a local drive instead of a network or external location.

6. Update QuickBooks Desktop

Running an outdated version can cause compatibility issues and QuickBooks Error 6123 Windows 10 / Windows 11 problems.

7. Use Verify and Rebuild Data Tool

This tool helps repair data integrity issues and resolve QuickBooks company file not opening problems.

Error 6123 in Multi-User Mode

QuickBooks Error 6123 in multi-user mode often occurs due to:

• Hosting enabled on multiple systems

• Database Server Manager not configured correctly

• Network data (.ND) file issues

Ensure hosting is enabled only on the server and all workstations are properly connected.

When to Seek Professional Help

If basic troubleshooting does not resolve the issue, the company file may be severely damaged. In such cases, professional QuickBooks Error 6123 support or QuickBooks hosting Error 6123 troubleshooting service is recommended to avoid data loss.

Experts can:

• Repair QuickBooks company file Error 6123

• Fix database server manager errors

• Restore damaged QuickBooks files safely

• Resolve network and hosting configuration issues

QuickBooks Error 6123 – Connection Lost While Opening Company File is a common but critical issue that can interrupt daily accounting tasks. By identifying the causes, applying the correct fixes, and maintaining proper network and hosting settings, you can prevent this error from recurring.

If the problem persists, contacting QuickBooks technical support Error 6123 specialists ensures a fast and secure resolution without risking your business data.