Luckily I've got Reaper and Sytlus RMX happily appeared and worked there - so I knew it was good.
When I Googled this problem a very old Ableton forum item (now locked) appeared suggesting that you remove the .dll (in this case it was Trilian) - rescan in Ableton, then put it back - rescan and see if it appears.
In desperation I tried this with Stlus RMX - and guess what it worked!
How odd? - Anyway here in case anyone else gets this issue
PC Win10 Clean Install and Build. Stylus RMX not in VST List
Re: PC Win10 Clean Install and Build. Stylus RMX not in VST List
Are all of your VSTs in the same folder? The only thing I could see is maybe the 64 bit version is in the wrong place. Reaper will pick up both bits of VSTs.
BTW how is W10 working for you?
BTW how is W10 working for you?