Quickbooks Connection Lost

Quickbooks Data Recovery and File Repair Support
Quickbooks Connection has been lost

Troubleshooting Error -6123

If you are not sure where to begin, step through each solution in order until the issue resolved.

Verify the network connection with the host computer

  • If you have a wired network, on both the host computer and the client computer trying to access the company file, check the network connections and cables to make sure they are secure.
  • Verify that other programs or resources located on the host computer are accessible. If not, restarting the host computer and then the client computer(s) may resolve the issue.

Note: If restarting the computers consistently resolves the issue, you might have an ongoing connection problem on the network. Because of the complexity and variety of both wired and wireless computer networks, Intuit cannot provide support for your network configuration. Please consult with your system or network administrator (if you have one), the vendor who set up the network, or a local computer consultant to troubleshoot connectivity issues in your computer and network environment.

Check firewall settings

If firewall software is installed, configure it to allow incoming and outgoing traffic to the following QuickBooks files and ports:

QuickBooks Version File Names Port(s)
QuickBooks 2009 and Enterprise Solutions 9.0


8019, 55333 to 55337, 56719
QuickBooks 2008 and Enterprise Solutions 8.0


QuickBooks 2007 and Enterprise Solutions 7.0


QuickBooks 2006 and Enterprise Solutions 6.0



For more information, refer to Configuring Internet security, personal firewall and parental control applications for QuickBooks updates.

Check for standby or hibernation mode on the host computer


Check the host computer. If it is in standby or hibernation mode, it can disrupt the QuickBooks connection with your company file, and you may want to disable or reconfigure those settings to prevent the connection from being disrupted in the future. Double-click Power Options in Windows Control Panel to modify the standby and hibernation settings. Consult your computer's user manual or Windows help system for details and information.

Fix damaged network data files (*.nd)

A network data file (.nd file extension) is a configuration file that allows access to a QuickBooks company file in a network environment.

On the computer that is hosting the QuickBooks company file:

  1. Right-click the Windows Start button and choose Explore.
  2. Browse to the folder that contains the company file.
  3. Right-click the file that has the same name as your company file and the file extension .nd (for example, MyCompanyFile.nd) and select Rename.
  4. Change the file extension to .ndold (for example, MyCompanyFile.ndold) and press Enter.
  5. Open QuickBooks and open the company file. QuickBooks will create a new network data file for the company file.

Toggle hosting off and on at the host computer

On the computer that is hosting the QuickBooks company file:

  1. Open QuickBooks and open the company file.
  2. Choose File >Switch to Single User Mode.
  3. Choose File >Utilities > Stop Hosting Multi-user access.
  4. Choose File >Utilities > Host Multi-user access.
  5. Choose File >Switch to Multi-User Mode.

Note: If you can't toggle hosting off and on, restart the computer in Safe mode with networking and try again.

Stop and restart the QuickBooks database service

On the computer that is hosting the QuickBooks company file:

  1. Stop the database server process:
    1. Right-click a blank space on the Windows taskbar and select Task Manager.
    2. Click the Processes tab.
    3. Click the Image Name column heading to sort the entries alphabetically.
    4. Right-click qbdbmgrn.exe and select End Process.
    5. Repeat step 1.d to stop all instances of qbdbmgrn.exe if it appears on the list more than once.
    6. Close Task Manager.
  2. Open the Computer Management window:
    • Windows Vista:
      1. Click the Windows Start button.
      2. Right-click Computer and select Manage.
        Note: You might be required to enter your administrator password.
    • Windows XP: Right-click the My Computer icon on your desktop and select Manage.
  3. Restart the database server process:
    1. In the Computer Management window, click the + symbol next to Services and Applications to expand the section.
    2. Select Services.
    3. In the Services window, click the Name column heading to sort the entries alphabetically.
    4. Right-click the appropriate service for your QuickBooks version and select Start:
      • QuickBooks 2009 or Enterprise Solutions 9.0: QuickBooksDB19
      • QuickBooks 2008 or Enterprise Solutions 8.0: QuickBooksDB18
      • QuickBooks 2007 or Enterprise Solutions 7.0: QuickBooksDB17
      • QuickBooks 2006 or Enterprise Solutions 6.0: QuickBooksDB
    5. Close the Computer Management window.

Set the correct folder permissions on the host computer

The folder on the host computer containing the QuickBooks company file must allow full control to all users, including the QuickBooks Data Server Manager user (QBDataServiceUser*).

To verify or set folder permissions for QuickBooks users, refer to the appropriate information for your version of Microsoft Windows:

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