Unsettled user removed counterfeits and shredded them into tiny pieces (8)
I believe the answer is:
confetti
'pieces' is the definition.
(I have seen 'pieces of paper' mean 'confetti' so perhaps 'pieces' could also mean 'confetti')
'unsettled user removed counterfeits' is the wordplay.
'unsettled' indicates anagramming the letters.
'removed' suggests deleting specific letters.
'counterfeits' with 'user' taken out is 'contfeit'.
'contfeit' with letters rearranged gives 'CONFETTI'.
'and shredded them into tiny' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for confetti that I've seen before include "Paper pieces festively thrown" , "Bits of paper scattered at festive occasions" , "Bits thrown at weddings" , "Paper used at weddings" , "Celebratory scraps of coloured paper thrown at weddings" .)