Apple is warning developers beta testing macOS Monterey 12.3 that they could encounter a boot loop if they use it on a Mac with macOS Catalina and FileVault enabled.
Apple issued its first beta of macOS Monterey 12.3 on Thursday, allowing participants in the Developer Beta program to download and try out the operating system update. In an update to release notes for the beta, it seems there's a chance some users could find themselves in trouble.
The warning, highlighted in red in the macOS Monterey 12.3 beta release notes, states that users of a Mac with macOS Catalina installed may have trouble testing both the Monterey beta and macOS Big Sur 11.6.4 beta, if they do so on a volume with FileVault enabled. Doing so "might cause a boot loop when attempting to log back into the previous volume."
While no reason is offered for why the problem occurs, nor how to solve it, there are a few ways that developers can avoid encountering the boot loop issue.
Apple does offer instructions for installing macOS onto a separate APFS volume, enabling testers to have the beta version running alongside the release variant. There is also the possibility of disabling FileVault on the volume before installing the beta, though this could take a long time to resolve.
Apple, and AppleInsider, strongly recommend users avoid installing betas onto mission-critical hardware due to the possibility of issues like this. Where possible, it is generally a better idea to install betas onto secondary or non-essential hardware, and to ensure there are sufficient backups of important data.