It sounds like the Micro-SD card is showing signs of a fault, or the partitioning is corrupt (which could depend how the image was copied onto the card). I’d suggest trying another Micro-SD card and/or giving this one a zero wipe.
If you have another Ubuntu desktop/laptop, you can install a utility named gnome-disk-utility which can present a GUI that can completely format (zero wipe) the card.
sudo apt-get install gnome-disk-utility
To run, type gnome-disks or access from the Accessories menu
You can also use this tool to wipe and restore the image back onto the card.
If you prefer the terminal, you can use dd:
sudo dd if=/dev/zero of=/dev/sdX
Replace X with the letter of the card. This is potentially dangerous! You could wipe another drive if you use the incorrect letter. Note that this cannot be done on the Pi since the card in use.
If you’re on Windows, the Disk Management program should allow you to delete all partitions and start over.