In most cases, it is not possible to run two antivirus programs simultaneously on a single computer. Even though users may be tempted to try to implement what they might regard as ‘dual protection’, there are good reasons why trying to operate two different antivirus products will normally cause difficulties.
Giving the antivirus scanner access to critical data
For effective antivirus detection — that protects against computer viruses, worms, Trojan viruses and more — the antivirus software has to be allowed to penetrate to a suitable level within the computer... deep into the system kernel. This is because the antivirus product needs to intercept system events, deep within the computer. The intercepted data is then passed to the antivirus engine for analysis — so the antivirus scanner can scan intercepted files, network packets and other critical data.
If there are two antivirus programs running on a single computer, they will each try to install interceptors into the same part of the system kernel. This is likely to result in conflicts between the antivirus monitors — probably with one of the following consequences:
- One of the two antivirus programs will fail to intercept system events.
- Each antivirus program’s attempts to install parallel interceptors will cause the entire computer system to crash.