ab1dll.dll is Trojan.Lineage-BB. ab1dll.dll monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\explorer.exe %System%\ab1dll.dll. More info: http://www.sophos.com/virusinfo/analyses... Removal: Remove ab1dll.dll from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.