A quick thought, FDEV seems to think the screenshot function in ED is working since it records a screenshot action, however the screenshot isn't getting written to disk. Is it possible that the folder the screenshots are supposed to be saved in is read only?
If you have EDDiscovery installed it will allow you to do an auto convert to a different format and specify a different folder, for instance I have a folder for my regular format screenshots and have EDDiscovery auto-convert screenshots to .jpg in a different folder. How about trying that and see if it works, if it saves the screenshot in an alternative folder it may be a permission problem in the local file system.
well, only for HD. Normal F10 does nowt. I did think permissions, but I can change stuff in the folder and surely the game runs under my context? EDD needs the file to be written first as it monitors that folder, and converts new files - so no help unfortunately
well, I was wrong about path not existing in the journal. not sure how I missed it before
{ "timestamp":"2017-10-05T08:30:09Z", "event":"Screenshot", "
Filename":"", "Width":7680, "Height":4800, "System":"Pleiades Sector IH-V c2-7", "Body":"Pleiades Sector IH-V c2-7 6 h a", "Latitude":-27.266603, "Longitude":-169.167969 }
Not that it's much help given it's blank.
Got my new GPU and thus removed the AMD drivers and installed the Nvidia.
Still no screenshot! (and disappointingly I still get frame drops

what IS it with this game? GPU is doing nothing (30%) but we drop to 57fps even on the spinny ship loading which make it stutter...grr....guess I need to get a gsync monitor now)
I ended up removing and reinstalling the game - no dice. Discovered windows 10 has a game mode (?) and the ability to record - didn't know that....verified it was all off and that any shortcuts were not F10. No joy.
So....with screenshots being kind of important for this game, and me itching to get going on the DECE, I decided to 'reset' windows 10 - which is essentially a fresh install. After installing the game installed, I copied the game files over to avoid needing to redownload. Voilla

It's all working again.
Shame we won't know what broke, but I really didn't want to waste another week of trial and error and still end up not fixing it. Appreciate the all the help Commanders