To support new features, each major release of QuickBooks changes the data
structure for company files. Because of this, once you work with a company file
in a new release, you cannot open that file from an earlier release.
Occasionally this problem also occurs with the incremental updates you apply
between major releases.
If you cannot open your company file, it could be because:
Your accountant made changes to the file by using a more recent update or a
later release of QuickBooks.
You work in a multi-user environment and someone else changed the file after
updating his or her copy of QuickBooks.
You reinstalled QuickBooks after updating it. If you reinstall QuickBooks,
you nullify any updates you have downloaded.
Always try updating QuickBooks first. To do this, open one of the sample
company files and choose Update QuickBooks from the Help menu.
If you have a backup of your company file, try restoring it.
As a last resort, upgrade your copy of QuickBooks to the latest released
General information about updating a company file to a new version of QuickBooks