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QuickBooks: COMException (0x80040408): Could not start QuickBooks.

Judah Sali

You may receive the following error when Sync & Save attempts to connect to QuickBooks:

  • System.Runtime.InteropServices.COMException (0x80040408): Could not start QuickBooks.

When Sync & Save attempts to connect to QuickBooks, if QuickBooks is not already running, then Sync & Save has to start up the QuickBooks process. If QuickBooks fails to start up successfully, then Sync & Save can not connect.

Please try the following steps to resolve this issue:

  • Make sure the Windows User Account Control (UAC) is set to the default security level. This setting is found under User Accounts in the Windows Control Panel.
  • Uncheck the "Keep QuickBooks running for quick startups." option found in QuickBooks under Edit | Preferences | General.
  • Turn off the Tools | Use Windows Task Scheduler option in Sync & Save. When this setting is turned off, you will need to leave Sync & Save open for scheduled jobs to run.
  • Try running the Sync & Save job at least once when QuickBooks is open.