Many people are unaware of the many issues the industry faces. Even the best antivirus software are susceptible to issues. Some are minor and easily be fixed, whereas others are more severe.
One of the main issues is that virus signatures do not provide enough to shield against a wide range of threats. It takes antivirus companies an extended time to release antivirus updates once new viruses are discovered. This is because they have to wait until their products recognize the virus and then send it in to be analysed.
The virus can spread and dozens, if not hundreds of computers are likely to be infected. It may also be transmitted to other networks. To be effective, anti-virus software needs be able to recognize and block such infections very quickly. This means that behaviour blockers or heuristic analysers are more effective than signature detection.
Incompatibility is a different issue. While the majority antivirus software developers put an emphasis on developing quality products and pay great attention to fixing bugs, the truth is that sometimes multiple antivirus programs can cause conflicts.