was there a drive plugged in there to a USB?
Also, can remove it from the fstab file in /etc folder and should solve the problem. It's trying to mount something not there during start up and fstab file entry is causing it.
When I turn on the operating system and try to boot up my computer . It trys to load for a minute then I get this error-- The disk drive for /mnt/usb-generic_sd_reader_2004888-0
is not ready yet or not present. OK I go into recovery mode and I get this -keys continue to wait,or press s to skip mounting or m for manual recovery-- I push s and it boots but I must be in recovery mode. Anyway the computer doesn't work well in this mode.

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