Most people do not realize the number of problems the industry has to face. Even the best antivirus software are susceptible to issues. Some are minor and can easily be addressed, while others are more serious.
One of the major issues is that virus-signature protection does not cover a wide variety of threats. It takes antivirus companies several months to release antivirus updates once new viruses are discovered. They must wait until the virus is spotted by their products and then sent to be analysed.
In the meantime, the virus is likely to spread, and it’s quite likely that dozens, if not hundreds of computers will be affected by the virus. It may also be spread to other networks. Antivirus software should be able to quickly identify and block these infections. This means that heuristic, or behavior analysers are more effective than simple signature detection.
Another issue is that compatibility issues between different antivirus programs is quite frequent. Although the majority of antivirus software developers concentrate on developing high-quality products and removing bugs it is true that different antivirus programs can occasionally cause conflicts.