MacOS "can't be opened because the identity of the devloper cannot be confirmed"

[Phil Harvey]

If you are using MacOS, you may have encountered a dialog similar to this when attempting to open files that were downloaded from the internet:

The reason for this is because MacOS adds a system XAttrQuarantine tag to files that you download.  Using ExifTool, you may remove this tag, thus allowing you to open the file.  The ExifTool command looks like this:

exiftool -xattrquarantine= FILE

After running this command on the file, you will be able to open it without being blocked by a dialog like above.

Specifically, for the above example dialog, you would run this command on the downloaded .dmg file before opening it:

exiftool -xattrquarantine= ExifTool-11.86.dmg

- Phil