What does Windows error code 1626 (ERROR_FUNCTION_NOT_CALLED) mean?

ERROR_FUNCTION_NOT_CALLED

ERROR_FUNCTION_NOT_CALLED means that Windows Installer did not execute the requested function or action. The exact reason depends on the API and context; for example, restricted package handles permit only a defined subset of actions.

Record which MSI function or action was requested and the type of handle or session used to request it. Correct the caller’s execution context when the operation is unavailable there rather than interpreting the result as package corruption.

What to check

• Record the specific MSI API or action name rather than treating 1626 as a package-install result.
• Verify the handle type, installer version, and whether the call is made from a custom action or restricted context.
• Review the documented return values for that API before adding a retry or fallback path.

Microsoft: MsiOpenPackageEx · Microsoft: custom action return values