So what I'm asking is, if you already have one antivirus installed on your android, will installing a second one cause problems? Will the first AV stop the second AV from working properly and vice versa?You have one antivirus installed on your phone. You suspect that your phone might have malware on it so you do a system scan and your AV doesn't find anything. So you decide to download another AV to see if it finds something on your system. You install the second AV while you still have the first AV installed on your phone, so now you have two antivirus programs installed on one phone. You do a system scan with the second AV and it doesn't find anything. This is about an unrooted android.