QuickBooks Error 3371 occurs when QuickBooks is unable to load the license data. This error is commonly due to a missing or damaged file, specifically the "EntitlementDataStore.ecml" file. It can be triggered by issues such as a failed or incomplete installation, system crashes, or hardware changes. To resolve this error, users can delete and recreate the "EntitlementDataStore.ecml" file, update Windows, or use QuickBooks Tool Hub for troubleshooting. This error prevents QuickBooks from opening and functioning correctly. For persistent issues, consult QuickBooks support or a certified professional for assistance at 1.855.409.2300