The term false positive is used when antivirus software wrongly classifies an innocuous file as a virus. The incorrect detection may be due to heuristics or to an incorrect virus signature in a database. Similar problems can occur with antispyware software.
On November 10, 2008, an update issued by AVG incorrectly identified user32.dll as being infected with either Trojan PSW.Banker4.APSA or Trojan Generic9TBN. When users clicked on the Heal button will bring up a Blue Screen of Death. Everytime users rebooted their machine, a BSOD will appear because of the deleted file. A fix has been provided by AVG.