It is sometimes necessary to uninstall and reinstall all other Intuit programs in the QuickBooks installation folder (as well as QuickBooks),  if QuickBooks does not function correctly after a reinstallation. This is referred to as a clean install.

Steps to resolve error, "An unrecoverable error has occurred. Exception msxml could not cocreate instance." This error, which occurs when opening QuickBooks, may be caused by a damaged or unregistered Microsoft XML Parser (MSXML).