Originally Posted by Emerson
Was there an interrupted upgrade? I'd run
apt-get update && apt-get upgrade
to make sure your system is consistent.
FYI: In LinuxMint, the mintupdate tool uses "levels" (Levels  Checked are 'default').
Using the above command in a terminal bypasses those Levels and applies all updates, regardless of the setting in the MintUpdate tool.
And the same goes for synaptic commands that do the same thing.
If you want to run only the "default" levels (or the levels you have chosen), open a terminal, if you can (try with ctrl+alt+t) and issue:
Have a Great Day!