Problem: Error 523:523 occurs on opening a PDF file in Internet Explorer when Trend Micro antivirus or related programs are active on your computer.

Solution: Add Acrobat, Reader, or both in the exception list of Trend Micro antivirus or related programs

Follow the steps:

  1. Quit Reader or Acrobat if it's running.

  2. Open Trend Micro antivirus from the shortcut on the desktop or from the Start menu in the taskbar.

  3. Select the Open the Main Console option.

  4. In the main console, click Device.

    Trend Micro console
  5. Click Configure for Security Settings.

    Configure security settings
  6. In the Protection Settings dialog box, click Exception Lists in the sidebar.

    Exception Lists
  7. Click the Add button.

    Add to the lists
  8. In the Add an Item dialog box, click Browse, and go to the following location and select the .exe file:

    • For Acrobat Reader DC: C:\Program Files (x86)\Adobe\Acrobat Reader DC\Reader\AcroRd32.exe
    • For Acrobat DC: C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\Acrobat.exe
    Browse and select the program
  9. Click OK.

  10. Click Apply and then click OK.

    Apply the selected program