The 'Connection Lost' error occurs when working in a QuickBooks company file:

Connection Has Been Lost

The connection to the company file has been lost. QuickBooks must close immediately. Any unsaved data will need to be reentered.

• The QuickBooks company file is stored on another computer or on a portable drive and connection to the storage device was disrupted
• Power management settings in Windows activated the sleep or hibernation mode on the computer storing the company file
• More than one computer on a network is configured to host the QuickBooks company file
• Computers in a multi-user installation are running different versions of QuickBooks
• Data in the company file is damaged

To resolve the issue, select the best solution for your situation. For example, if you use the company file on a network, check network connectivity. Or if you recently updated QuickBooks to a new release, make sure all workstations installed the new version. If you don't know which solution is best, start at the beginning and perform all steps that apply to your configuration of QuickBooks.

• The QuickBooks company file is stored on another computer or on a portable drive
  • If your company data file is stored on another computer, make sure you are still connected to that computer over the network. One way to test network connectivity is to try opening another file or folder on the computer that hosts the company file. Restarting the workstation or the host computer will sometimes fix a lost connection. If the connection problem persists, check your computer hardware or network configuration.

Note: Wireless networking is not supported for QuickBooks. For more information, refer to Compatibility of different network types with QuickBooks.

• Power management settings in Windows activated the sleep or hibernation mode on the computer storing the company file

Open the power management settings in Windows Control Panel and disable all sleep, standby, and hibernation modes on the computer where the company file is stored:

• Windows Vista: Choose Start > Control Panel > System and Maintenance > Power Options.
• Windows XP: Choose Start > Control Panel > Power Options.

Refer to Windows Help and Support for more information about Power Options.

• More than one computer on a network is configured to host the QuickBooks company file
  1. Ensure that hosting is enabled on the computer that stores the company file:
     • If the QuickBooks application is installed on the computer:
       1. Open QuickBooks.
       2. Choose File > Utilities:
          • If Stop Hosting Multi-User Access appears on the menu, hosting is enabled and you can proceed with the next step.
          • If Host Multi-User Access appears on the menu, select it to enable hosting on this computer and proceed with the next step.
     • If the QuickBooks application is not installed on the computer (server-only installation):
       1. Double-click the QB Database Server Manager icon in the Windows system tray (or choose Start > All Programs > QuickBooks > QuickBooks Database Server Manager).
       2. Click the Database Server tab.
       3. Verify that your company file appears in the window below Currently connected company files and logged in users. If it isn't there, click the Scan Folders tab and click Help for information about adding the company file.
       4. Minimize the QuickBooks Database Server Manager window.
          
          Important: Do not click Close or the X in the upper right corner of the window. Both of those will close the application and file hosting will stop on the computer.
  2. Ensure that hosting is disabled on all other workstations that use the company file:
     1. Open QuickBooks.
     2. Choose File > Utilities:
        • If Stop Hosting Multi-User Access appears on the menu, select it to disable hosting on this computer and proceed with the next step.
        • If Host Multi-User Access appears on the menu, hosting is already disabled and you can proceed with the next step.
     3. Repeat step 2 on all remaining workstations.

• Computers in a multi-user installation are running different versions of QuickBooks

Update QuickBooks to the latest release on all computers that use or host the same company file:

• If the QuickBooks program is installed:
  1. Open QuickBooks.
  2. Choose Help > Update QuickBooks.
  3. Click Update Now.
  4. Close and reopen QuickBooks after the download is complete.
  5. Click Install Now when the QuickBooks Update Service window appears and prompts you to install the update you just downloaded.
  6. Repeat steps 1 through 5 on all workstations where the QuickBooks program is installed.
• If only the QuickBooks Database Server Manager is installed (server-only installation):
  1. Double-click the QB Database Server Manager icon in the Windows system tray (or choose Start > All Programs > QuickBooks > QuickBooks Database Server Manager).
  2. Click the Updates tab.
  3. Click Check online for the latest version and follow instructions to install the latest release.

• Data in the company file is damaged

If the previous steps do not resolve the issue, or if you have a single-user installation of QuickBooks on the same computer where the company file is stored, data may be damaged in the company file. Run the Verify utility to detect data damage, and then run the Rebuild utility to repair it:

1. Open QuickBooks and open your company data file.
2. Choose Window > Close All.
3. Choose File > Utilities > Verify Data.
   • If the message QuickBooks detected no problems with your data appears, your data is not damaged. Click OK and stop here.
   • If the message Your data has lost integrity or A data problem prevents QuickBooks from continuing appears, data is damaged. Proceed to the next step to run the Rebuild Data utility and repair the damage.
4. Choose File > Utilities > Rebuild Data.
5. Click OK to the warning message requiring a backup of the company file before starting the rebuild.
   
   Important: Do not replace your current backup. Intuit recommends using a newly formatted external media source for this backup (such as a CD or DVD). If necessary, back up to your local hard drive.
   If a message appears asking if you want to replace the backup file, click No. To avoid overwriting the current file, enter a new name in the Filename field.
6. Click OK at the bottom of the QuickBooks Backup window.
   
   Important: If the backup process fails, click Cancel at the Rebuild prompt. Do not continue the Rebuild process with your original company file if the backup process does not complete successfully. This can lead to permanent data loss. You must make a copy of the company file and attempt the Rebuild process again using the copy of the company file. Rename the copy of the company file with a unique name to avoid confusion with the original file.
7. The Rebuild Data utility starts as soon as the backup process completes. Click OK when the Rebuild has completed message appears.
8. Close and reopen QuickBooks and your company file.
9. Repeat step 3 to rerun the Verify Data utility.
10. • If the message QuickBooks detected no problems with your data appears, your data was repaired successfully. Click OK.
    • If the message Your data has lost integrity or A data problem prevents QuickBooks from continuing appears, QuickBooks was unable to repair the data damage. Restore your company file from a recent backup or contact Quickbooks Data Recovery for more information about data recovery options.