The company has clarified that currently it is only testing the auto-uninstall feature with Windows Insiders running build 18351 or later from the 19H1 branch. The build is part of what will become Windows 10 version 1903, which Microsoft is expected to release in March or April.
Microsoft's original support note didn't state which version of Windows 10 could automatically uninstall buggy updates, only that Windows would do it if it detected a startup failure.
Despite its presence in the latest Slow ring release, Windows Insiders wouldn't have known the auto-uninstall feature is there unless they'd experienced a startup failure.
The new support note includes a disclaimer that the auto-uninstall feature has not been released publicly, a screenshot of the error message, plus some more context around when an update might be uninstalled.
Microsoft explains that uninstalling an update is "only done as a last resort".
"Occasionally, startup failures can occur due to hardware issues, file corruption, or incompatible third-party software," Microsoft notes.
"If Windows detects that your machine cannot start up successfully, it will try to diagnose and resolve failures due to disk issues, system file corruption, invalid registry keys, or other such causes.
"If all these steps are unsuccessful and your machine is still unable to start up properly, Windows will determine if the startup issue was introduced after recent driver or quality updates were installed. If so, these updates may be uninstalled automatically to get the device back to a workable state. This is only done as a last resort."
Microsoft has also given more context around blocking removed updates from installing automatically for 30 days.
The company now says it will block them if Windows detects that removing the buggy updates enables a machine to boot successfully.
The idea is to give Microsoft and third parties time to investigate the failure and resolve any issues. Previously, it only said it would block certain updates for 30 days without explaining that the block would only be in place only if it detected that uninstalling specific updates actually resolved a startup failure.
Users will still have the option to manually install the updates if they believe the updates should not have been uninstalled.