1. Find the file format (.pdf .docx .lnk) of the Attachment that is blocked
2. Close Outlook
3. Open Regedit
4. Navigate to:
   1. HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security for Outlook 2016
   2. HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security

For Outlook 2010

5. Right click and select new then String Value

6. Then Enter “Level1Remove”

7. Press enter

8. Right click the string value then click modify

9. Type the file name you want to open then press enter (if you want to add multiple file types format it like .docx;.com