Mac Guard is a fake rogue anti spyware program that is infects the Mac OS. This virus is usually spread via email / spam / hacked websites.

How To Remove Mac Guard From your Mac:
First click on empty portion of your desktop so that the Finder is selected. Once it is selected, click on the Go button and select Utilities, Locate the Activity Monitor icon and double-click on it. This program lists all the processes that are currently running on your Mac OS Scroll scroll down until you find the process named MacGuard, Once the process is selected click on the Quit Process button. When a prompt appears asking if you are sure you want to quit the MacGuard process, please click on the Force Quit button. When you have finished, Mac Guard should no longer be running on your Mac and you can now close the Activity Monitor and the Utilities window. While still at the Finder, click on the Go button and select the Applications menu option here scroll through the list of programs until you see a program named MacGuard. When you find the program, right-click on it and select the Move to Trash menu option. If MacOS prompts you for your password, please enter it. The MacGuard application will now be removed from the operating system.

Now click on the Apple Menu and select the System Preferences menu option. When the System Preferences screen opens, select the Accounts option under the System category. When the Accounts screen opens, click on the Login Items button. This will open a screen, similar to the one below, that displays a list of programs that will automatically start for this particular user when they login to the operating system. Look through the list of programs that are starting automatically, and single click on the entry named MacGuard. Once it is selected, click on the minus (-) sign button, Once you click on the minus button the Mac Guard entry will be removed and MacOS will no longer attempt to start it when you login. The files below are created by Mac Guard and should be removed once this malware has been removed.

/Applications/MacGuard.app
/Applications/MacGuard.app/Contents
/Applications/MacGuard.app/Contents/Info.plist
/Applications/MacGuard.app/Contents/MacOS
/Applications/MacGuard.app/Contents/MacOS/MacGuard
/Applications/MacGuard.app/Contents/PkgInfo
/Applications/MacGuard.app/Contents/Resources
/Applications/MacGuard.app/Contents/Resources/About-Back.png
/Applications/MacGuard.app/Contents/Resources/About-Mail.png
/Applications/MacGuard.app/Contents/Resources/About-Phone32x32.png
/Applications/MacGuard.app/Contents/Resources/About-Ticket.png
/Applications/MacGuard.app/Contents/Resources/AboutD.nib
/Applications/MacGuard.app/Contents/Resources/AboutMBMI.png
/Applications/MacGuard.app/Contents/Resources/CC-Back.png
/Applications/MacGuard.app/Contents/Resources/CC-BigOptions.png
/Applications/MacGuard.app/Contents/Resources/CC-BigOptionsHover.png
/Applications/MacGuard.app/Contents/Resources/CC-BigOptionsPressed.png
/Applications/MacGuard.app/Contents/Resources/CC-BigScan.png
/Applications/MacGuard.app/Contents/Resources/CC-BigScanHover.png
/Applications/MacGuard.app/Contents/Resources/CC-BigScanPressed.png
/Applications/MacGuard.app/Contents/Resources/CC-BigSysInfo.png
/Applications/MacGuard.app/Contents/Resources/CC-BigSysInfoHover.png
/Applications/MacGuard.app/Contents/Resources/CC-BigSysInfoPressed.png
/Applications/MacGuard.app/Contents/Resources/CC-CleanupBtn.png