-Clear Browsing Data ( Settings/Privacy )
-Reinstalling the plugin by logging to Battlelog again
-In the search bar typing the following command: chrome://plugins
-Checking the box Always allowed for ESN Sonar API and Battlelog Game Launcher
-Restarting the Browser
-Log back into Battlelog via Origin (Play from Battlefield4 icon )
-Join a Server
The only one that worked for me was to type chrome://flags into your address bar and hit enter. Scroll down and enable 'Enable NPAPI' and then enable the one below that 'Native Client' (both were set to disable by default).
Then restart your browser and have a go at re-installing the new plugin.