Microsoft tightened security in the Windows 10 Version 1709 Fall Creators Update (FCU), but unfortunately, the tightening adversely affects the performance of applications that use the Win32 GetPixel API. Visual Assist is one such application so initial opening of editor windows in Visual Studio, when Visual Assist is active, can be extremely slow.
You can speed up the opening of edtor windows when using Visual Assist to pre-FCU levels by disabling Control Flow Guard for Visual Studio. Navigate to:
Windows Defender Security Center | App & browser control | Exploit protection settings | Program settings | Add program to customize | Add by program name
Be cautious and choose the exact file path(s) for Visual Studio, or disable protection for any application named “devenv.exe”.
Scroll to disable Control Flow Guard (CFG).
You might improve the performance other aspects of Visual Assist in Visual Studio, at least with respect to the effects of tighter security in the FCU, by disabling all 21 program security settings specific to the application.
Apply, and restart your PC.
You can improve performance of all affected applications in the FCU by disabling CFG at the system level:
App & browser control | Exploit protection settings | System Settings