Few people realize how many issues the industry faces. Even the most effective antivirus software can have problems. Some are minor and easily be dealt with, while others are more severe.
One of the main issues is that virus signatures do not provide sufficient to guard against a variety of threats. Whenever new viruses appear it takes time before antivirus companies are able to make and release new antivirus updates. They have to wait until the virus is avast ultimate vs avg ultimate identified by their products and then sent to be analysed.
The virus is likely to spread and dozens or even hundreds of computers could be affected. It could also spread to other networks. Anti-virus software must be able to quickly detect and block these infections. This means that heuristic, or behaviour analysers are more efficient than simple signature detection.
Another issue is that incompatibility between different antivirus programs is quite frequent. Although the majority of antivirus software developers put an focus on developing high-quality products and pay tremendous attention to removing bugs, the reality is that there are times when multiple antivirus programs can cause conflicts.