Recently, Google Chrome blocked Adobe's PDF plug-in and replaced it with their own. To fix:
- Go to settings in chrome
- Click "show advanced settings" at the very bottom of the Settings page
- Under Privacy, click "content settings"
- In the dialog that comes up, scroll to Plugins, and click the link that says "Disable individual plug-ins"
- Look for and disable Adobe Reader
- Look for and enable Chrome PDF Viewer.
You may also want to update your Adobe Reader and Adobe Reader plug-in. To do so, open Adobe Reader on your computer. Go to the "Help" menu and click "Check for Updates."