With Logic 9 i have some problems using GURU (newest version)...
1. Sometimes when i open the plugin in logic, there s no gui. only a white/blank window!
(i have that only with guru! not with bfd, native instruments, etc.)
2. i have started new tracks using GURU... if i add a new sampler plugin (eg exs24) and want to save the song there comes an error message "ALERT! GURU save error #006a" AND i can't open the instance of GURU anymore
2x 3ghz quad-core intel mac / 8GB ram / OS X.5.7 / 2x Metric Halo 2882 / UAD2quad / SSL Duende (3.0) / Powercore X8 // USB: Virus Ti / MPD32 / NI KORE (2.1) // a lot of 3rd party plugins...
Are you running some other big plugins in the session or is this with Guru on its own? It sounds a bit like you're running out of RAM inside Logic.. although you have 8GB in the machine, Logic itself can only use ±3, including all the plug-ins.