Multiple (many) identical error messages from Finder regarding "Time Machine" disk.

[macmesser]

I'm running a High Sierra classic Mac Pro 5,1 and using Time Machine on an eponymous external USB 3 disk. Recently, I started experiencing an odd phenomenon. Background story: My Mac will sometimes hesitate for some time before waking from sleep mode. I believe a backup is being run when this occurs. It seems that by turning my track pad and/or monitor off and then back on I can prompt it to wake up, but after some minutes. However, this is not the "main event," which is as follows: When the Mac does wake up, I have a whole column of 30 or more Finder messages which read, "Disk Not Ejected Properly¬ Eject 'Time Machine' before disconnecting or turning it off." These messages are present sometimes after the Mac wakes up naturally. I have not been disconnecting nor turning off the "Time Machine" disk. What could be causing Finder to think that I am?

PS- I noticed that I am getting another set of finder messages: "The disk you inserted is not readable by this computer" followed by buttons to ignore, eject, format. No disk inserted.

 

[Brian33]

I'm just guessing, but I wonder if the external drive is going bad. My understanding is that a failing drive can present symptoms like taking a long time to satisfy requests from the host. It seems to me that could explain the slow wakeups and "disk not ejected" messages.

How old is that external USB drive?

 

[macmesser]

I'm just guessing, but I wonder if the external drive is going bad. My understanding is that a failing drive can present symptoms like taking a long time to satisfy requests from the host. It seems to me that could explain the slow wakeups and "disk not ejected" messages.

How old is that external USB drive?

Thanks for reply. Good thought. The drive is not very old. A few years, maybe 4 at most, but it's only been in service for two years or so and only as a Time Machine disk. I bought 2 of them on sale. They are Seagate 7TB USB 3, designed for storage and backup and they might be of a particular design that is not optimized for speed but for economy of production. I'll run some diagnostic programs (Tech Tool Pro and Drive Genius) I have on them.