A few cases of this have been reported which appear to be specific to Mountain Lion 10.8. You will need to adjust your security settings to allow installation of all applications, including those downloaded from the internet. Making this change should resolve your problem and allow the installation to proceed.
Typically, you will see an error message prompt like this. Follow the directions below to resolve this.
Directions:
1. Open the System Preferences. This can be done by either clicking on the
System Preferences icon in the
Dock or by going to
Apple Menu > System Preferences.
2. Open the Security & Privacy pane by clicking
Security & Privacy.
3. Make sure that the
General section of the the
Security & Privacy pane is selected.
Click the icon labeled Click the lock to prevent further changes.
4. Enter your username and password into the prompt that appears and click
Unlock.
5. Under the section labeled
Allow applications downloaded from:, select
Anywhere. On the prompt that appears, click
Allow From Anywhere.
6. Exit System Preferences by clicking the red button in the upper left of the window. You should now be able to install GoAnywhere OpenPGP Studio as well other applications downloaded from the internet.