Facebook's new feature of video calling, powered by Skype, is not supported for all Operating Systems.

The video calling is supported by Firefox, Chrome, Safari and Internet Explorer on Windows, Mac and Linux OS but it doesn’t work in the pre-released version of Mac OS X. Facebook video calling is blocked on Mac OS X Lion browsers.

If you try to make a video call using your Mac OS X Lion, you will see the video call button go grey with a notification saying, “Not supported in this browser or OS version.

However, BestTechie suggests a way by which you can change your browser's user-agent to trick Facebook into thinking you are on a compatible OS.

Here’s how you can enable video calling in your Mac OS Lion:

On Safari
Go to System Preferences and under the advanced tab, enable the developer menu. On the menu bar, click on the Develop option. This will change the user-agent to something that will be compatible with the Facebook video calling service.

On Google Chrome
To enable the function in Chrome you can either run the following command on terminal
open /Applications/Google Chrome.app –args -user-agent=”Mozilla/5.0 (Macintosh; U;Intel Mac OS X 10_6_8; en-us) AppleWebKit/525.19 (KHTML, like Gecko) Version/3.2.1 Safari/525.19?
download and install User-agent Switcher extension to navigate to browsers and then select it as user agent string.

On Firefox
To enable it on Firefox you have to download the plugin as in case of Chrome and navigate to http://facebook.com/videocalling.

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