Digidesign has announced that Pro Tools HD 7.4.1 software is now compatible with Mac OS X 10.5 (Leopard) on 8-Core Mac Pros (with Intel “Harpertown” processors).
Expanded Mac OS X 10.5 (Leopard) support will be announced later, and Digidesign asks that users wait for further announcements before upgrading to Mac OS X 10.5. Check the company's Pro Tools HD 7.4.1 Intel Mac Support page for detailed Pro Tools HD 7.4.1 compatibility information.
Registered Mac Pro-based Pro Tools HD 7.4 users can download the Pro Tools HD 7.4.1 software update for free at www.digidesign.com.
Also, note that some plug-ins and virtual instruments are not compatible with Pro Tools HD 7.4.1 running on Mac OS X 10.5.1, and some require that you update your plug-ins if an update is available. Before you install the Pro Tools HD 7.4.1 update, review the plug-in compatibility and update information here.