This article below will provide the different ways in which the QuickBooks Unrecoverable Error may be quickly fixed and the ways in which one and all can perform troubleshooting at the click of a finger.
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Update QuickBooks:
Ensure that you are using the latest version of QuickBooks. QuickBooks releases updates and patches to fix bugs and improve stability.

Run QuickBooks File Doctor:
QuickBooks File Doctor is a tool provided by Intuit to diagnose and fix various issues. Download and run this tool to check for and repair errors.

Regards,
Peter