How to Use Windows Antivirus & Quarantine Tool to Manage DLL Files

• Heuristics: new or uncommon DLLs may trigger “suspicious” behavior detections.
• Bundled installers: temporary unpacked DLLs under %Temp% look unusual.
• Tampering or corruption: altered signatures or mismatched versions raise alerts.

1. Open Start → type Virus & threat protection and open it.
2. Confirm definition updates are current (see Protection updates).

1. Click Scan options.
2. Run a Quick scan first; follow with a Full scan.
3. If threats persist or files are locked, use Microsoft Defender Offline scan (restarts into a trusted environment).

Inspect blocked items and restore only if you’ve verified they’re safe:

1. Open Protection history.
2. Filter to Quarantined/Blocked and check the DLL’s path and threat name.
3. If legitimate, choose Allow on device or Restore after you validate the file.

Use exclusions sparingly and remove them when done.

1. Go to Virus & threat protection settings → Manage settings → Exclusions → Add or remove exclusions.
2. Click Add an exclusion → choose File (preferred) or Folder and select the DLL or installer folder.
3. Complete the required action → remove the exclusion.