Last week, I downloaded an updated version of Adobe Reader. I did not select it as my Safari pdf reader. Nonetheless, it has replaced Preview as the default pdf reader in Safari. How do I get rid of Adobe Reader as the default pdf reader in Safari and replace it with Preview?
You can open the Preferences in Adober Reader, select the Internet options and uncheck the first two options (Display PDF in browser using: and Check browser settings when starting Reader). The next time you open Safari and click on a link to a .pdf, Safari will open it. It always worked for me in different versions of Reader, Safari and Mac OSX.
I just tried your tip & it works! However, I also discovered that you shouldn't make the change in Reader while Safari is running & then check for installed plugins (in Safari's help menu) ... unless you like to see Safari crash! 🙂