More on how Windows File Protection works. I think this key
paragraph from the MS doc explains why various solutions appear to
work -- but may not be permanent:

"WFP protects system files by running in the background and detecting
attempts to replace protected system files. WFP is triggered after it
receives a directory change notification on a file in a protected
directory. Once this notification is received, WFP determines which
file was changed. If the file is protected, WFP looks up the file
signature in a catalog file to determine if the new file is the
correct Microsoft version. If it is not, the operating system
replaces the file with the correct version from the dllcache
directory or the distribution media."

So WFP only kicks in at the point when you add/delete/edit a file in
a protected directory. This would seem to explain Scott's success
with editing FILELIST.XML in safe mode and rebooting -- WFP must be
off in safe mode. Presumably, if Scott in any way modifies
FILELIST.XML it will trigger WFP, which will will try to fix it.

Regards,
Andrew Ferguson