Hello WarrenStreet,
Thanks for reaching out to Apple Support Communities. Upon review of your post, it seems that you are unable to automatically mount multiple external storage devices on your Mac. We can see why you’d want this taken care of if you frequently work with these drives, so let us help from here! To start us off, we advise that you back up your Mac and update it to the latest macOS version, Monterey.
Once that has been completed, test to see if the issues with the drives persist. If they do, we suggest that you continue by testing to see when this behavior occurs.
First, put your Mac into safe mode and test. Booting into safe mode will disable any startup and login items from automatically opening, which can help us to isolate the source of the issue further. When you do this, you’ll see some unusual behavior from the display; this is to be expected. Please follow the steps in this article: How to use safe mode on your Mac.
Next, let's see if this behavior persists in a second user account on your Mac. Please follow these steps to make a test account that can be deleted later: Set up users, guests, and groups on Mac.
Please let us know how these tests go. We're here for you. Have a fantastic day!
