This free service scans the file against over 70 different antivirus engines and will tell you if any have flagged it as malicious. 2. Check the File Properties
If it is sitting in C:\Windows\System32 , it is trying to pass as a system file.
Because Dynamic Link Library ( .dll ) files contain executable code that can interact directly with your system, you should handle unrecognized DLL files with caution. Here is how you can safely investigate it: 1. Scan it for Malware
