QuickBooks Error 15101 happens when the software fails to update properly, generally due to restricted folder permissions or antivirus intervention. This problem can prohibit payroll or product upgrades, disrupting business operations. Running QuickBooks as an administrator, modifying security settings, or fixing the installation to restore functionality are the usual methods for fixing problems. For assistance and advice with QuickBooks, call 1.855.738.2784 to speak with an expert.