QuickBooks error code 15215 is a payroll update related error that can also occur when some other program runs at the background conflicts with the QuickBooks software. Sometimes, the QuickBooks error 15215 also occurs when the firewall blocks or quarantines the QuickBooks files and when the program is not correctly installed properly. The problem can be easily fixed by restarting your computer or else you will need to take some specific measures. The first step involves logging in to your Windows computer and using QuickBooks with full administrator permissions. The next step includes restoring the advance settings (internet options) and using internet explorer as a default browser. If still, the problem doesn't resolve, you will need to restart your computer in selective startup mode and then re-configure the firewall settings to mark QuickBooks as a genuine program. Contacting the experts could be the last resort if nothing of the above tips worked well.