I had the same problem but it was related to the Game DVR function of Windows 10. I tried killing off a bunch of different programs (antivirus, various other things) to no avail. Finally, I did the following which seemed to work:
- Start Menu > Settings > Gaming
- Game Bar: Turned off Record Game Clips, unchecked Show Game Bar when I play full screen games Microsoft has verified
- Game DVR: Turned off Background Recording
- Game Mode: Turned off Game Mode
BTW, this isn’t an “official” support response. This is just what worked for me once I got the Windows 10 Creator’s Update and GW2 kept failing to launch.
(edited by BobbyStein.2315)