Along with the OS X 10.7.3 update, Apple issued Security Update 2012-001 for Snow Leopard to address a number of security vulnerabilities in the latest version of that OS.
After installing the update, a number of people have found that Rosetta applications no longer work properly, and are reporting problems with applications crashing, no longer being able to perform tasks like saving files, or having problems with services like printing.
Rosetta is a dynamic instruction translator for PowerPC code that allows PowerPC-based programs to run on Intel CPUs. This technology allowed for a relatively seamless transition to Intel CPUs in 2006, giving developers time to build native Intel versions of their programs.
Rosetta was available in OS X up until Snow Leopard but was left out of OS X Lion, a decision that forced a number of people to stay with Snow Leopard in order to continue using their PowerPC applications. Unfortunately for these people the latest security update has broken some aspects of Rosetta's functions, which is now causing their PowerPC applications to not work properly.
Overall the main issues appear to be with file saving, printing, and whether or not programs will quit or open, which indicates a possible problem with filesystem management and specifically the ability to create new documents or temporary files for performing save and print operations, but the situation has yet to be thoroughly investigated. Additionally, the problems being experienced do spread to other application behaviors as well, making troubleshooting and pinpointing an exact cause a bit difficult to do.
If you still rely on PowerPC programs and have not yet installed the latest security update for Snow Leopard, then you might consider holding off for now until these issues have been addressed. If you have already installed the update and are experiencing these issues, for now there are two potential approaches you can take:
- Reapply combo updater
The first option is to download the latest OS X 10.6.8 Combo update and apply it. This update was released before the security update and applying it might revert some changed files that could be responsible for the problems being experienced. This is not guaranteed to fix the issue, but is a good first step to take before reverting to a system backup.
- Revert to backup
If you cannot get the problem to clear by reapplying the latest Combo update, then the next best option would be to revert to a system backup created before updating the OS. Hopefully you have Time Machine set up or had otherwise fully backed up your system before applying the update, and can restore the backup to your system to restore Rosetta functionality.
To restore a Time Machine backup, first boot to your OS X installation DVD (insert it and reboot with the C key held down), followed by choosing the option to restore from backup from the Utilities menu. In the restore window select your Time Machine drive and the backup instance you want to restore (make sure it is the one immediately before you applied the Security update). It may take a while, but when it's complete, restart your system and you should be up and running again.
(Thanks to MacFixIt reader "Jcerro" for writing in about this.)
UPDATE: MacFixIt reader Jmorris wrote in suggesting at least in some instances this problem has to do with the way Rosetta interacts with Apple's ImageIO framework, and has made available an altered version of the framework that might help people who are experiencing the problem. If after updating you are not able to open your PowerPC programs, then you can download and install the patch from here. A number of people who have applied the patch have reported it fixing their systems, though some others have also reported it not working for them.