In /usr/bin/mcheck line 39:
mdir ${DRIVE}'*'
     ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
mdir "${DRIVE}"'*'


In /usr/bin/mcheck line 53:
if mtype -/ ${DRIVE}\* > /dev/null; then
            ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
if mtype -/ "${DRIVE}"\* > /dev/null; then

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...