> Randomly ejecting external SSD Why does my external SSD keep getting randomly disconnected from my MacBook Pro?
Disconnection, or unexpected ejection, is most commonly associated with sleep and wake events. External solid–state drive (SSD) enclosures often put themselves to sleep when not active, especially those drawing power over their connection, but that shouldn’t unmount or eject them from your Mac. When your Mac goes to sleep, it shouldn’t automatically eject attached drives, although rarely macOS may not be compatible with the drive, and it gets ejected in error. To be certain, check that you’ve disabled the setting to “Put hard disks to sleep when possible,” in the Energy Saver pane. Some hardware configurations do have problems, though. If an external SSD is connected to a USB–C port on an external display, then macOS is likely to power down those USB–C ports when it puts that display to sleep. At present, there’s no way to prevent this from happening apart from stopping the display from going to sleep, preferring a screensaver instead. In the Energy Saver pane, set the top slider to Never turn that display off. Unexpected ejection at other times suggests a faulty drive or Mac, or software which is being affected by a serious bug. This is very difficult to diagnose, because the only evidence is buried in the log, which isn’t easy to access. The free log browser Ulbow may be the best tool to resolve this, because it can look back in the log to past events. It’s easy to recognize wake events with the message “PMRD: System Wake,” and the article at bit.ly/mac351brwlg provides a walkthrough.