Many users forget to "safely remove" an external storage device before shutting down the OS (DON'T ASK!!
).. and then we remove it! On the next start up, the OS cannot find that drive.. and a 'ghost' drive can haunt you.
Any type of external hard drive, camera or flash memory association should be "removed" when done with it, prior to shutting down of the OS. Any folders or files that were opened prior to the shut down will remain in a search criteria at the next start up, otherwise. Similar too with any associated Intranet path. Shut down the 'guest' or 'visitor' source before the primary host is shut down.. or phantom folders and files may be flagged.
F@H.. to solve mankind's maladies.. in our lifetimes!