Disk not ejected properly message in Sonoma

I had the same issue. I now use auto shutdown at night and auto start up in AM. To use this you would need to use a terminal command.

I have almost the same issue. LaCie hard drive. As soon as I initiate a backup to the external HD, I get the Disk Not Ejected Properly error message. The backup never completes, actually never really gets started. If I don't do any thing the icon for the drive will reappear on the screen, then the error messages pops up. This will happen over and over again. I will also get the error message if I try to explore the HD using finder.

Same here to a degree. Adapter A to C <-> USB C hub (external power) <-> Qty 5 USB drives (2 for backup). Seems like it happens when a backup kicks off but it also seems to happen randomly. My worry is a backup kicks off when another program is accessing a different USB drive. Do I feel confident. Not so much. Since this is a new Macbook Pro, I'll be following this closely.

I have this aswell and it is caused here because I use an USB A to USB C adapter. I am not concerned about this, my backups are working fine