The recent Insider preview builds for Windows 10 are somehow throwing a System Service Exception error in green screen as win32kbase.sys fails to load. The problem occurs when playing certain games on the affected machines.
The problem started with the release of Insider Preview build 18282, but the most recent preview build 18290 has the problem as well. Microsoft acknowledged the issue in build 18282 and promised a fix in the next build (which is 18290). But as per the user reports, the latest preview build still carries the bug.
The GSOD win32kbase.sys error has been annoying users a lot as certain games are unplayable due to the issue. For Overwatch players, the green screen error shows when users try to join a server in the game or as soon as a map finishes loading. The same is for Rainbow Six as well. It crashes as soon the game menu loads. So far the following games and apps have been affected by this problem: Dirt 3, Dirt 4, Grand Theft Auto V, Forza H3, Forza 7, Planetside 2, Rainbow 6, Overwatch, AutoCAD 2018.
FIX: Roll back to a stable build
Microsoft promised a fix in the Insider build 18290, but it has clearly failed to deliver. To fix the problem now, you have got to roll back to a stable build of Windows 10 OR if you’ve a restore point for the build 18272 or earlier, rollback to that.
It might be possible to roll back to a stable build (without deleting apps) if you’ve joined the Insider Preview Program in the last 10 days. Go to Settings » Update & Security » Recovery » and click the Get started button under “Go back to an earlier build” section.
If neither rolling back to an earlier build or restoring from a restore point is an option for you. Then you probably have to wait for Microsoft to fix the problem in the next Windows 10 Insider Preview build OR clean install the latest stable build of Windows 10 on your PC.