Earlier this week, Microsoft rolled out a new cumulative update, labeled as KB5001391, to Windows Insiders in both Beta and Release Preview channels. This brought the News and Interests feature, previously exclusive to the Dev channel, to those users.
However, it seems that the update might be causing some major issues for some users, as they're experience bugchecks resulting in green screens of death (GSOD) - the equivalent of BSOD for Insiders - specifically mentioning a BAD_POOL_CALLER error. The bugcheck apparently happens soon after starting the computer, making PCs essentially unusable. Users have also reported that uninstalling the cumulative update solves the problem.
The issue doesn't appear to be very widespread, as there are only a few reports to be found in the Feedback Hub and on Reddit that we could find. We also haven't experienced any issues on our machines running Windows 10 version 21H1.
Finding some issues with Insider builds is not something that should surprise users, but a system crash like this is probably more than most are ready to handle, especially for users in the Release Preview ring, who probably expect builds that are nearly ready for general availability. If you're interested in checking out News and Interests, you may want to hold off on installing the update.
If you happen to have already installed the update and you're experiencing issues, you can head to Settings -> Update and Security, and click View update history. Then choose Uninstall updates, and find KB5001391, then uninstall it and restart. You may also want to head back into Settings and pause updates for a few days until a fix is made available.
Update: Twitter user Cristian Rodríguez seems to have found another workaround for the crashes. Uninstalling the Intel Rapid Storage Technology (RST) driver should also fix the issue for those interested in testing the newest build.