my file explorer (caja on Ubuntu Mate 18.04) is suddenly showing 2 mounted devices
efi. My hard drive is not mounting now.
What might be the problem?
There only possibility I can think of is that a recent update caused the appearance of drives/partitions on your pc. On my pc
filesystem is merely a shortcut to your root folder.
efi means Extensible Firmware Interface system partition or ESP is a partition on a data storage device (usually a hard disk drive or solid-state drive) that is used by computers adhering to the Unified Extensible Firmware Interface (UEFI).