I downloaded File Extension Changer Portable_v3.3.1 from Softpedia:
I extracted this portable app to a USB flash drive and created a few folders and files for a test.
They were definitely not write-protected.
File Extension Changer is displaying an error message. (See pasteboard image.) I'm not working
with any write-protected files or folders, so there must be another explanation for this error box.
This system is in my home office, so I have full administrative rights. Critical system files are the
only fully protected files.