QBregistration.dat is QuickBooks Desktop installation file containing license information that is retrieved and validated every time QuickBooks Desktop is activated. If this file is damaged, QuickBooks Desktop will not open and you will need to recreate qbregistration.dat as part of troubleshooting.
Locate your license and product numbers
Log into My Account to view the license numbers of all your QuickBooks products, or you can try the following:
If you previously registered your QuickBooks software, you can get help finding your license number or key code with our License and Key Code Lookup tool.
(ProAdvisors: This tool will not work for licenses included in your ProAdvisor software package, but it will work for copies of QuickBooks you ordered separately.)
If you haven't registered your product, contact us for support.
Make sure you have the required proof of purchase
FOR MULTIPLE VERSIONS OF QUICKBOOKS INSTALLED ON ONE COMPUTER, include an additional copy of the italicized text (from) in qbregistration.dat file. This copy should be pasted after </VERSION>. You will need to replace the boldface items in the new section with the appropriate values corresponding to each unique version of QuickBooks.