If you are upgrading to OS X Mavericks and get stuck in a boot loop that will not complete the installation, you may need to hit a special key combo to force the computer to complete the installation and upgrade process.
Gotta Be Mobile reader Steve Small reached out to let us know about the OS X Mavericks Upgrade boot loop problem, which forced his MacBook Pro to get stuck showing the odd text on a screen below, which looks like a OS X crash and an error message that says, “Your computer restarted because of a problem. Press a key or wait a few seconds to continue startup.”
Ultimately this error prevented Small from upgrading to OS X Mavericks, as it did many other users. Thankfully if you get stuck in this OS X Mavericks boot loop you can press four keys at startup to reset the NVRAM and get past the boot loop.
When you restart the Mac, press Option-Command-P-R until you hear the startup sound a second time. This will reset the NVRAM, which is where your Mac stores the following information.
- Speaker volume
- Screen resolution
- Startup disk selection
- Recent kernel panic information, if any.
In this case, resetting the NVRAM should clear up the boot loop issue which was possibly related to the startup disk selection stored here or to a kernel panic. The error screen shown at the top of this guide looks very similar to a kernel panic.
With this out of the way you should be able to continue the upgrade to OS X Mavericks. If the computer does not pickup where it left off you may need to go to LaunchPad and select Install OS X Mavericks again. If you need to install it from scratch, here is our guide to a clean OS X Mavericks install.
Apple released OS X Mavericks as a free upgrade to all Mac users with a compatible Mac in October. The software update is available for many Macs as old as mid-2007 are compatible with the free update. Users can download the 5GB installation file from the Mac App Store on any of these compatible devices.