Mac OS X Lion introduced iOS style automatic termination for applications. If an application is running for a long period but is inactive, the operating system will automatically terminate, close and quit, the application. With auto resume it can be invisible to the user that the application was ever terminated.
I prefer the built-in Preview app to Adobe Reader and I have the OS configured to open PDFs in Preview.
After upgrading to Lion, Preview would sometimes hang with a spinning cursor. This would happen when I already had a document open in Preview and I clicked a PDF link in Safari.
If Preview is quit it seems to AutoResume without any issue. So the next suspect to investigate was AutoTerminate.
Here’s how to disable auto terminate for Preview:
- Open Terminal
- Run the following command:
defaults write com.Apple.Preview NSDisableAutomaticTermination -bool yes
I commonly have Preview open and running usually with software development related material. With AutoTerminate disabled I no longer get the spinning cursor hang.