Computer and Software Support

Anti-virus not detecting virus

There is various reasons an anti-virus program will not detect a virus.

Anti-virus program not up to date

New viruses come out daily. The anti-virus program cannot detect the virus if the program is not aware of the new virus. The program detects the virus by comparing files to its information about viruses. If the virus is not listed in its database, it will not be detected.

There is many free anti-virus programs out on the market. They do a great job but one of the downfalls of it being free, is that some do not do automatic updates. The user has to manually update the software. They do this to motivate the user to purchase the product. If the program has only manual updates, there is a great chance that the software will not be updated in time.

Fix... Update the anti-virus and then run the anti-virus. NOTE: you may have to run the update more than once till it says there is no more updates.

Anti-virus company has not written code for the virus

If the virus is new, the anti-virus company may not be aware of the virus or hasn't written code for it yet.

Fix... contact the anti-virus company for options.

The anti-virus program is not a good product

There are good products and bad ones on the market. You should research the product before using it.

Fix... Google anti-virus programs and research for a good anti-virus program

The system is infected before the anti-virus program was updated

A virus can disable or hinder the anti-virus program from working or detecting the virus if the virus is on the computer before the anti-virus has received the signature of the virus to detect it.


  1. Run the anti-virus program and then try to update it. If it will update, then run a scan again.
  2. Take the hard drive out and connect it as a slave on another system and scan it with that anti-virus

Once it is clean, make sure the anti-virus is up to date.