End of day, not start - let out to make trouble (8)
I believe the answer is:
unsettle
'trouble' is the definition.
(thesaurus)
'end of day not start let out' is the wordplay.
'end of day' becomes 'sunset' (I've seen this before).
'not start' means to remove the first letter.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'sunset' with its first letter taken off is 'unset'.
'let' anagrammed gives 'tle'.
'unset'+'tle'='UNSETTLE'
'to make' acts as a link.
(Other definitions for unsettle that I've seen before include "disturb with lunettes" , "Disturb the calm or stability of" , "Upset" , "Discompose" , "Make uneasy, disturb the calm of" .)