How to stop issues with external drive unmounting in Catalina

So I just got an external HD for media, etc. I have an iMac running Catalina. Every time the computer goes to sleep, it seems to unmount the external drive (with two partitions, “Media” and “Untitled 2”). Then, it will give me an ABSURD number of notifications. For example, I stepped away for a few minutes to help my child with an assignment and got 50 notifications (25 apiece).

Is there a way to make sure that the Mac unmounts the HD before going to sleep? Also, is there a way to clear these notifications without clicking each one?

I wonder why there are so many notifications.

You could use an app like Jettison from St. Clair Software to unmount the disk before the Mac sleeps.

I think it’s doable with Keyboard Maestro too, but am not sure on top of my head.

edit: it might be a more complicated issue: look at this jettison faq that goes deep into problematic behaviour of power nap and other things

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Your barrage of notifications “Disk not ejected properly” immediately reminded me of a similar problem with one of my portable disk drives a while back. The problem was a faulty USB3 cable. The cheap USB3 cables supplied with low-end consumer-grade external drives are notoriously fragile and unreliable.

I replaced the cable with one of these (USB-A to micro-B):

Now no more problems with that disk drive. This cable is stiff and much thicker than the small-diameter cables supplied with external disk drives. But it works. I recommend that anyone who uses the small external drives keep at least one extra USB3 cable on hand. Also, handle those small, fragile cables carefully.


That reminds me that I had had some similar software in a past life that stopped being updated.

Yes this seems worth a look thank you

If replacing the cable does not resolve the issue, another place to check is the micro-USB connector in the disk drive housing - these are fragile also. There could be a hard-to-diagnose problem with the drive connector instead of the cable. Using the new cable (or a known good cable), connect the disk drive and gently wiggle the cable where it plugs into the disk drive connector. If the drive immediately dismounts or ejects, you have your answer.

Another check is to try connecting that drive using a known good cable to another computer to determine whether it will maintain a stable connection.

Another good troubleshooting step is to connect a different disk drive and cable to your computer. I like to buy these inexpensive disk drives in pairs. One reason is to back up one to the other; another reason is troubleshooting if needed. If the different disk drive maintains a stable connection, you have ruled out your computer and software as the culprit. The problem would then be narrowed down to your new disk drive, its connector or its cable.

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