Yes, we all know the importance of having an anti virus running in our machine, but an expert cautioned, multiple anti virus is not a good idea at all.
First, the two enabled anti-virus will try to kill each other. How? These security programs consistently send information about your system, other anti virus may see it as a malware, so it will attempt to block and remove it.
Second, when a threat is detected, an anti virus will remove and quarantine it. At the same time, the other anti virus will continue to detect the threat either it will remove and or quarantine according to its programmed objective causing bogus warning messages.
Final reason is that it will eat up your resources bringing down the performance of your computer.
Worth noting advice from Serge Malenkovich of Kaspersky:
When it comes to protecting your computer, more protection is not better. Take some time to do the research and choose one comprehensive antivirus suite that has been independently tested to combat the latest known malware programs and that will singlehandedly arm your system to the teeth to protect it against every type of threat.