Symptom
The application Mail may temporarily stop responding when you open an attachment that causes the Classic environment to start up. A spinning disc cursor may be visible during this period.
Solution
This delay and spinning disc cursor are normal while Classic starts up. To avoid the Classic startup delay while using Mail, you can set Classic to start up when you log in. Follow these steps:
1. Open System Preferences.
2. Click Classic.
3. Click the checkbox to select the "Start up Classic on login on this computer" option.
A future release of Mac OS X may change this behavior.