80040408 - Could not start QuickBooks, Windows Vista & Windows 7 Users 

Windows Vista & Windows 7 Users ONLY
You will receive this error if:

• The User Account Control (UAC) is set to "OFF.  This setting is found in the Control Panel-->User Accounts section and must be set to "ON" (as recommended by Microsoft).
• Your QuickBooks file resides anywhere other than the PUBLIC folder in a network environment or the PRIVATE (Your User Account) folder in a single user environment.
• Both QuickBooks and CAPS/CPS/WMS must be run with Standard User Permissions (NOT elevated to run as Administrator).

For additional information see Quickbooks Connection Errors .