A Software Update for Thunderbolt was just one of many Apple releases that went public yesterday, but unlike the rest, you should be in no hurry to pick this one up. Many users who have installed the update are reporting that it is causing boot failures and more on their Mac.
According to Apple’s release notes, the update “Adds support for the Apple Thunderbolt to Gigabit Ethernet Adapter.” The problem is, it also adds a number of serious issue. Some users are reporting that they are now experiencing boot failures, kernel panics, and “unexpected error” messages. The only way to fix them is by reinstalling OS X.
For some, the update isn’t causing any problems at all. However, it’s hard to establish whether this is a problem with certain Macs, or whether there’s a pattern to the issues.
If you’re having issues, TidBits notes that you can enter Lion’s Recovery Mode by holding down Command+R while your Mac is booting up. If, for any reason, you don’t have a recovery partition or yours is damaged, your Mac should automatically enter Lion Internet Recovery, which allows you to download the system again.
The only problem with this, of course, is that it takes time.
Once you’re back up and running, you’ll probably have updates to install via Software Update. Just be sure you don’t accidentally install the Thunderbolt update again.
Source: TidBits