Ever since I switched to OS X, I have never really paid much attention to viruses or trojans, but one can not overlook at times the feeling of “uneasiness” by not having antivirus installed.
I tried out the latest version of Kaspersky Anti-Virus 2011 for Mac on my MacBook Pro (2011 with 8GB RAM) and although I did not find any malware, trojans or viruses, the biggest “virus” for me was Kaspersky itself.
In order to scan for viruses, Kaspersky installs kernel extensions and I found that after installing the application, my MacBook (running a 480GB SSD drive) would not shutdown at all. Deleting Kaspersky (which then invokes CleanMyMac to delete preferences) by moving it into the trash, also did not resolve the problem.
I found today, that the only way to completely remove Kaspersky (and it’s kernel extensions which have been the cause of OS X not shutting down) is to remount the install DMG and then select the uninstall option.
This completely resolved the problem and my MacBook Pro now shuts down in 3 seconds as I was accustomed to.