QuickBooks: The application trying to connect to QuickBooks is not supported while multiple instances of QuickBooks are running.

This error may occur when using QuickBooks in multi-user mode in a terminal server environment.

Resolution 1:
  • Log in to QuickBooks using the QuickBooks user account assigned to Sync & Save.
  • Uncheck the option "Keep QuickBooks running for quick startups" found under Edit | Preferences | General | My Preferences.

Resolution 2:
  • Log in to the Terminal Server using the Windows user account under which Sync & Save will run.
  • If you wish to use QuickBooks, log in under any QuickBooks user account. When you are finished, choose File | Close Company/Logoff.
  • If you do not wish to use QuickBooks, log in to QuickBooks using the QuickBooks user account assigned to Sync & Save and then choose File | Close Company/Logoff.
  • Leave the QuickBooks window open.
  • Do not log off the terminal server session, instead just close the connection.

Feedback and Knowledge Base