RStudio crashes when saving in OS X

If you are using RStudio on versions of OS X prior to 10.9 Mavericks, you may see RStudio crash when you try to save a file. 

This behavior is caused by having a version of Safari earlier than 6.0. If you do an Apple System Update and update Safari to 6.1 or later this should not occur.

If for some reason you are unable to update Safari and are still seeing this problem, you can instead fix this by going to the Accessibility options in System Preferences -> Accessibility and uncheck the option "Enable access for assistive devices".