PUM.Optional.HijackExefiles is Malwarebytes’ detection name for a potentially unwanted modification that changes the default association of files with an .exe extension. This usually results in users being unable to run any programs.
The following registry value data are modified:
the default value is changed.
Malwarebytes can modify this registry value data back to its Windows default setting without user interaction.
When a Potentially Unwanted Modification (PUM) is detected on your computer, Malwarebytes for Windows does not know whether it was authorized. Optimization software, malware, and Potentially Unwanted Programs (PUPs) are known to make these types of changes, hence they are regarded as potentially unwanted by design.
To have Malwarebytes for Windows ignore a PUM, you must add the PUM to the Allow list. Here’s how to do it.