For some reason, Logic seems to be giving the most problems with GPO. Nevertheless, many users are making great music with Logic. Some of the issues have to do with either bugs in Logic, the way Logic handles MIDI, and issues with the Kontakt Player. Must issues have been resolved with the latest version of Logic Pro and the Latest Kontakt update. More issues are expected to be resolved with the next updates. Logic also experiences the 'stuck note' problem mentioned above. Below are two other important issues:

• Logic 'Graphic Offset Bug' (mouse pointer is noticeably off) - This is a bug in Logic which effects Native Instruments products and the word from Emagic is that this has been fixed in the upcoming version of Logic Pro and that the fix will be implemented in the other Logic versions soon. We've heard from some users that this problem no longer exists in the new version of Logic.

USER WORKAROUND submitted by Christian Bocher
"Open Logic. (Autoload in my case) Logic goes through it's paces but does not load up an arrange page. The Logic headers are all there tho. -go to "File" -choose "Open Recent" and pick a song that has already been worked on and preferably gui issue free. (at this point if I were to choose "open" and search for the song I wanted, the gui issue would be there) _once the bug free song has been opened you can navigate to autoload or any other song you like..."

USER WORKAROUND submitted by Jean Pierre Brie "1:
Start logic from a document icon not from the application icon! 2-voilà! Or: 1: Start logic from application icon 2-close autoload 3-open new document (or old ) from the document icon after that do as you always did until the next reboot!"

• Logic 'Reset to "0" Bug
This is a concern with GPO which relies heavily on the mod wheel. The design of Logic is such that the Mod Wheel Date resets to "0" whenever you hit stop. Since ModWheel controls volume, users can't hear their music when they hit play again.

USER WORKAROUND: Submitted by Peter Delano
Peter Delano has created two Logic Song files. The first environment allows you to convert incoming Mod Wheel data information into track automatation data. This will avoid the "return to zero" bug in Logic. The second converts Mod Wheel, CC#20, #22 & 24 into automation data. The first one deal with only mod wheel whereas the second one incorporates track-based automation control of GPO's other control parameters (portamento, and the 2 variation knobs) and includes a few cable switchers for working with multiple GPO instances. These will automatically set the cc#1 data to user defined values. Here are the LSO (Logic) files: GPO Logic 1 (106KB) GPO Logic 2 (198KB)

(from garritan.com)