I'm upset with guards making errors (10)

I believe the answer is:

misentries

'errors' is the definition.

'i'm upset with guards' is the wordplay.
'upset' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'guards' becomes 'sentries' (sentry is a kind of guard**).
'im' backwards is 'mi'.
'mi'+'sentries'='MISENTRIES'

'making' acts as a link.

I've seen this clue in The Telegraph.

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