The Windows 10 Insider Preview Slow Ring – the beta track that is meant to receive only those builds that are free of any known serious problems – has not received an update for months. While the fast ring is currently testing previews of the April 201
9 release, codenamed 19H1, and the even-quick skip-ahead ring is not previewing the release of October 1919, 19H2, but of the April
2020 , 20H1, the Slow Ring is still receiving a single 19H1 build
This has prompted some concern among insiders that perhaps the ring has been forgotten about, and it has even caused a few complaints from companies that are using Windows Insider for Business program to validate new Windows releases before their launch. Without Slow Ring builds to test, there is nothing to validate, meaning that they will have to delay deployment of 19H1 once it ships
Microsoft's Dona Sarkar, chief of the Windows Insider program explained yesterday what the problem is and in many ways it's a throwback to Windows' before the days of DEP and ASLR and PatchGuard and all other measures Microsoft has implemented to harden Windows against malicious software: the build is crashing when some unspecified common anti-cheat software is used. Sarkar's tweet says that the software causes a GSOD, for Green Screen of Death; (19659004) The fast ring builds have the same issue with GSOD, the traditional and disappointingly familiar Blue Screen of Death, which indicates that Windows has suffered a fatal error, is colored green for preview releases so they can be distinguished from a glance from crashes of stable builds. , and indeed, it has been listed on their known issues list for many months.
Sarkar says the fix must come from the third-party company that developed the anti-cheat software. Often when compatibility issues arise, Microsoft will modify either Windows or the errant application to ensure that it continues to run, but anti-cheat drivers have a different story entirely. They run in kernel mode (hence the GSOD when they crash) and routinely tamper with pieces of the operating system that they're not supposed to tamper with. It is possible that this particular driver is doing nothing forbidden and using only officially allowed hooks within the kernel to do its business; it's also very likely that it messes with things it would not mess with and damaging data structures or kernel
Either way, there seems to be something of an impasse. Microsoft has not reverted any change that is causing the crashes in the first place, but it has been a problem for months and has a significant impact on the company's Windows 10 testing infrastructure. The entire test pipeline has been seized due to this GSOD problem. Amid concerns that Windows 10's testing already has too many gaps and leaves too many bugs unresolved, the April 2019 update is off to a rocky start, and it's not even finished yet.