updated 02:00 am EDT, Tue June 19, 2012
Caused kernel panics, freezes on some machines
After causing problems for some users including serious boot issues that left them unable to easily access their Macs, Apple pulled a Thunderbolt Software Update (labelled v1.2) from its available downloads last Thursday, June 14. Today the update, which is meant to allow Thunderbolt-equipped Macs to use the new Thunderbolt-to-Gigabit Ethernet adapter, reappeared with a 1.2.1 version number.
While MacNN has received reports of users who installed the previous version of the update without issue, enough customers were apparently affected that the download was removed and re-tooled to address the problem. Some users were forced to completely re-install Lion on their Macs in order to un-do the damage caused by the previous version. While reports of any user data lost haven't been see, some users had to rely on either the built-in recovery partition in Lion or a longer Internet-based recovery system to get back up and running.
As is normal for a re-issued update, Apple does not provide any history on the previous version. The new version will be available through Software Update to affected Macs or available through Apple's support site and is expected to replace the 1.2 version even where successfully installed. The update is 520kb in size and requires OS X 10.7.4.