Thanks for the reply! It crashes the AU validation. I am using osx 10.6.4. I did try re-installing and trashing the cache file located at Library/Cache/com.apple.audiounits.cache
Im not sure what you mean by nad pref files, but I can't find any prefs for Altiverb.
I made the mistake of force quitting while altiverb was scanning for an ir folder. Now it crashes Logic. Here is the screen I get when trying to manually open it with the AU Manager. I have tried removing, reinstalling, and trashing the cache au file.
Thanks in advance for any help.