If you see "disk not ejected properly" on your Mac Pro (2023)
Find out what to do if an internal SATA drive unexpectedly disconnects from your Mac Pro.
Certain models of internal SATA drives may unexpectedly disconnect from your computer after your Mac wakes from sleep. This can occur if your Mac automatically goes to sleep or if you manually put your Mac to sleep. If you see a message stating that your disk was not ejected properly, you can restart your Mac to reconnect to the drive.
To prevent your Mac from automatically going to sleep, change the sleep settings on your Mac:
Choose Apple menu > System Settings, then click Displays.
Click Advanced, then turn on "Prevent automatic sleeping when the display is off".
Click Done.
Apple is aware of this issue and a resolution is planned for a future macOS update.