QuickBooks error code 15103 occurs when a user tries to update the software or payroll function. One of the possible reasons for this error is an incorrect configuration. The error hinders the user from accessing the latest features that come with the update and makes downloading, updating, installing, or uninstalling difficult. Additionally, the error occurs in multi-user mode, preventing access to the company file. The error message appears in two forms: "Unable to open the update program" and "Update program is damaged."