When doing software updates, "QuickBooks Error 15101" pops up, which denotes problems with the Windows Firewall or security settings. The update process is interfered with by this error. To fix the problem and properly upgrade QuickBooks to the most recent version, users must check firewall permissions, change security settings, and guarantee reliable internet connectivity. 1.855.738.2784 QuickBooks Experts Team is available right away if you need help.