bacon wrote in reply 2 above:
"macOS will try to index all files in the drive in the background for Spotlight"
You can prevent that by doing this:
Connect the external drive. Open a window so you can see "the root level" of the drive.
Then, type "command-shift-period" to make all normally-invisible files visible.
Now, open up the Text Edit app.
Type in a few characters (doesn't matter), how about "stop spotlight" (that's all that's needed).
Now, you need to save the new file.
Navigate so that it will be saved to the root level of the external drive.
Give it this name EXACTLY:
".metadata_never_index.txt" (without quotation marks)
MAKE SURE you include the period at the begining and the underscores.
The period at the beginning of the name will make the file invisible later on.
Now, to finish up, type "command-shift-period" again (to make the invisible files, invisible again).
WHY we did this:
With this file in place so named, spotlight will ignore the drive and NEVER index it. Hopefully, this lack of activity will keep it cooler.
