macOS Monterey 12.3 reportedly bricking Macs with replacement logic boards

Apple MacBook Air

The macOS Monterey 12.3 update, released on Monday, is reportedly causing problems for users attempting to update from macOS 12.2.1 or earlier. According to support forum posts, users are seeing errors, endless restart loops, and possible bricking of their devices.

Reports indicate that only Mac devices with a replacement logic board are affected by the issue.

Although the macOS Monterey 12.3 update appears to be bricking some Mac devices, other reports indicate that an affected Mac could also reboot without the update being successfully installed. In these cases, users report seeing an "iBoot Panic" message."

Similar threads have been popping up on Reddit as well, Thursday's initial report by MacRumors notes. The website's own forums have even more accounts.

Users can reportedly fix their bricked Macs by booting it into DFU mode and reviving it manually. However, the process requires that they have a second Mac handy.

Some users also report successfully installing macOS Monterey 12.3 on a Mac with a replacement logic board using IPSW files. However, like reviving a Mac in DFU mode, this method requires a second Apple computer to perform.

In at least some cases, users who have taken their Macs to Apple for service say that technicians simply replaced the logic board on their devices again. But, the second repair apparently doesn't do anything to mitigate the problem.

Apple has instructions on how to revive an Apple Silicon Mac device here, as well as how to revive an Ints-based Mac device here. The company has yet to acknowledge the problem with macOS 12.3, however.

This isn't the only issue that users have reported with the latest macOS update. On Tuesday, reports surfaced of macOS Monterey 12.3 causing performance or speed issues for users that rely on PCI-E external GPUs.