If when attempting to run QBI you get the following error:
System.Runtime.InteropServices.COMException (0x80040400): QuickBooks found an error when parsing the provided XML text stream.
two different solutions have been found to resolve this depending on the situation:
User had installed QB web connector which causes the issue with QBFC5 unable to connect properly QuickBooks and QBI. The solution was to uninstall QB web connection, reboot, re-install and re-register QBFC5, and then was able to run QBI again
All QuickBooks related programs had to be removed and the registry edited removing all references to QuickBooks and then reinstalled
delete all QuickBooks / Intuit programs and files in Program Files and Common Files
manually edit the registry removing all remaining references to QuickBooks and Intuit
install QuickBooks and apply latest updates
now able to run QBI successfully
Do note both instances of this occurring the issue occurred with QBI 18.104.22.168 It is possible that QBFC5 is the reason for both having occurred, whereas QBI 5 uses QBFC7 the latest development control from Intuit.