I'm assuming Windows? I think its a Windows Antivirus block that can be overridden. Try this
-
Open "Windows Security" (this is the new hub/home of Defender)
-
Go to "Virus & threat protection" on the left sidebar
-
Click "Protection history"
-
Here you'll see a list of the last actions Windows Defender took - it'll say "Threat removed or restored" or something along those lines - click on it and confirm the file name and you can then "Allow" the threat from here
-
This will then add the filename/file to the "Allowed Threats" section and won't bug you again for that file!