In case IE (Internet Explorer) requests a plug-in to be reinstalled even when installed.
Please follow the instructions below.

1. Update the firmware to the latest version.

2. Register the camera’s IP at the View Compatibility Setting.

     IE — Setting — View Compatibility Setting — Enter Camera IP — Add

3. Register a camera IP at a trustable site.
  
    IE — Setting — Internet Option — Security — Trustable Site — Site — Register Camera IP (http://192.168.20.120)

4. Security Level Setting
      IE — Setting — Internet Option — Security — Trustable Site — Minimum Security Level — User Level — Check Unsigned Active X Control Download

5.Change Plug-in status as Enable at Additional Function Management
      IE — Setting — Additional Function Management — Select «All Additional Functions» from Display — Set Techwin Camera Plug-in as enabled