HP ProDesk 400 G4 Maintenance And Service Manual page 86

"Illegal Operation has Occurred" error message is displayed.
Cause
Software being used is not Microsoft-certified for your version of
Windows.
Configuration files are corrupt.
78 Chapter 6 Troubleshooting without diagnostics
Solution
Verify that the software is certified by Microsoft for your version
of Windows (see program packaging for this information).
If possible, save all data, close all programs, and restart the
computer.