Remove MacDefender from Your Mac

Actually, MacDefender is not a virus. It also is not a malicious that will removes your data or send spam emails to your friends. Basically, this application tries to make you pay some money for similar applications, as is commonly found when you have to pay a 'Pro' version of any application. The difference, MacDefender have no the pro version, do not spread the infection, viruses, or other things that make problems to your Mac.

Here’s how to clean your Mac from MacDefender:

1. Click the Spotlight (magnifying glass which located in the top right corner).
2. Type in 'Activity Monitor' and press the Enter button
3. In the Activity Monitor, click on the Process Name column to sort the list by Process Name.
4. In the list, find MacDefender. Select it and click the Quit Process button.
5. Click Force Quit in the confirmation window and enter your Password if prompted.

After the process has been stopped, now you should to delete it:

1. On your dock, click Application folder.
2. Find MacDefender and drag it to the Trash.
3. Empty your Trash.

And the last procedure, you have to remove MacDefender's last trace.

1. Again, click the Spotlight.
2. Now, type 'Accounts' and press Enter.
3. In the left-pane, select your user profile.
4. In the right-pane, click Login items tab.
5. In the list, find MacDefender and click the 'minus sign button'.

That's all, hope it useful :)
Via proposedsolution.