QuickBooks POS – Invalid Product Number: Error 176109

Solution 1: Delete the contents of the entitlement client folder

1. Using Windows Explorer, navigate to: C:\Program Data\Intuit\Entitlement Client\v8.
2. Press the CTRL+A on your keyboard to select all the files in the folder, then press Delete.
3. Select Yes to confirm the action.
4. Relaunch QuickBooks Desktop Point of Sale and re-register the application.

Solution 2: Rename the WSActivity file

1. Using Windows Explorer, navigate to: C:\Program Data\Intuit\QuickBooks Point of Sale XX\Ini
2. Right-click WSActivity and select Rename.
3. Enter OLDWSActivity and click anywhere to save.
4. Close the window then delete the entitlement again.
5. Relaunch QuickBooks Desktop Point of Sale.