Ok so i'm happily coding along and out of the blue this happens after a save and closing VS then later opening the program:

host-mingw32.c*:192: Attempt to access invalid address
Error compiling project sources
Build failed for project 'DAC4_05_06_2025'

This is not the first time.  I always have to, then, open the program and its files with Arduino and do a save as to a new folder with a file name then open the new version in visualmicro.  This does not happen with Arduino (ever)  but is getting to be a common error with VM.  Is this a BUG and/or is there a way i can fix it without having to jump through all the hoops? FYI, i am using the latest version as far as I know...
Using teensy 4.1

Arduino is set to Faster,  VM is set to Fastest.

The build folder can be cleaned using Build > Clean <ProjectName>, or to clear everything for the solution (including the cached shared core) Build  > Clean Solution.

The same problem appears to have affected Arduino IDE in the past as well:
https://forum.pjrc.com/index.php?threads/compilation-fails.75089/

It may be best if we ensure the *.gch file is cleaned every build (as it is generated with the prebuild1 hook), which would avoid the issue recurring in the future.

We will update with any changes, and if desired we can supply a workaround prebuild hook to apply to the project to clear the *.gch file in the interim.