Solution 3: Determine if QBDataServiceUserXX is damaged
On your keyboard, press Windows+R to open the Run window.
Type in services.msc, then select OK.
Right click the service that matches your version and select Properties.
QuickBooks 2018: QuickBooksDB28
QuickBooks 2017: QuickBooksDB27
QuickBooks 2016: QuickBooksDB26
On the Log On tab, select Local System account, then select OK. Note: This is not a permanent solution. Leaving the service logged on as Local System account is a security risk, and this option should only be enabled temporarily for the purpose of completing the troubleshooting step.
Close the Services window and open QuickBooks. If QuickBooks opens without errors: