A client was tired of using and paying for Norton Security for the Mac. Tired of the program slowing down their computer and of seeing messages “incompatible with this Mac OS”. So, I started to uninstall Norton from four Mac computers. Then I ran the special uninstall Norton tool for the Mac on all the computers. After restarting the computers, I downloaded Avast for the Mac started to install that security replacement. Avast refused to install and said that Norton is still on the computer. So, after scouring the Internet for about an hour, I found the answer. Boot the Mac into Recovery Mode (Start the Mac and hold down the Command and R key simultaneously. At the MacOS Utilities screen, click on Utilities Then click on Terminal, While in Terminal Mode Type in these to commands –
Cd /Volumes/Macintosh\ HD/Library/StagedExtensions/Library/Extensions
Then press Enter and type –
rm –rf NortonForMac.kext
This allows a manual deletion of the last remnant of the Norton Security program, a kernel extension named NortonForMac.kext . After deleting these kernel extensions, Avast installed without a problem.