Forest have failed to find the net in two Championship games so far. Their latest shut out came away at Millwall, who found the net on two occasions courtesy of Darius Henderson and Liam Trotter at the New Den.
After the match, former England boss McClaren revealed that his new club are not currently posing too much of a threat in the final third of the pitch.
"If we'd played until Sunday we wouldn't have looked like scoring," McClaren told reporters.
"That's two games now, Barnsley and Millwall where, to be perfectly honest, we've not looked like scoring.
"The difference in this league is scoring goals and we haven't looked like doing that so that's something we need to address quickly."
The Tricky Trees are away again in midweek, this time facing a trip to Doncaster Rovers on Tuesday, August 16.