I recently ran into an issue with my PHP files being downloaded instead of displayed. I run multiple sites on a MediaTemple (dv) server. All the sites I setup previously were unaffected, but this new site was still having issues with all PHP files. This issue is actually with the Parallels Plesk Panel.
Upgrading Parallels Plesk 10.4
When you upgrade to Parallels Plesk Panel 10.4, the Plesk control panel changes quite a bit. It appears that some of the defaults change, too.
Login to Plesk as the specific webspace that you are having trouble with.
Click the “Websites & Domains” tab.
Scroll to the bottom and click on the name of your domain.
There are quite a few options on this page. They used to be enabled by default, but now you have to manually enable them after setting up a domain.
To enable PHP files to display (instead of download), you need to check the box that says “PHP Support”. It’s up to you how to run it, but the default used to be “as Apache module”, so unless you have reason to change it, I recommend sticking with that.
The image below shows what all the default options used to be. If you are running Ruby on Rails, or any other platforms, you’ll want to enable them as well.
SSL Support on MediaTemple (dv) Server
The SSL Support is only needed if you are using an SSL. Don’t worry that there are no SSLs listed. The actual SSL certificate is assigned & managed at the main server level. So as long as you’ve set that up properly on the server, checking this box is the last step you need to enable SSL for the domain.