The Gang Exploits the Mortgage Crisis - S5-E1
Continuity mistake: After Dennis, Charlie and Mac kick apart the family's front door, the amount of damage to the door decreases significantly when Frank begins questioning the lawyer.
The Gang Reignites the Rivalry - S5-E12
Continuity mistake: When Dee is practicing cup flipping in front of Mac and Charlie, all the cups are right side up. In the next shot one is lying on its side without her knocking it over.
Mac and Dennis Break Up - S5-E9
Continuity mistake: After Mac throws water on Dennis, the size of the water stain on his sweater changes throughout the scene.
Mac and Dennis Break Up - S5-E9
Continuity mistake: Frank puts his hands up when Dee grabs the hammer near the end. In the very next shot, his hands are down.
The World Series Defense - S5-E6
Continuity mistake: Ron is pouring alcohol into gallon jugs. He starts to pour the liquid in one angle. The shot changes angles, and he's no longer pouring it.
The D.E.N.N.I.S. System - S5-E10
Continuity mistake: When Dennis is playing the voicemail from Caleigh, the way he holds the phone changes between shots.
Mac and Dennis Break Up - S5-E9
Continuity mistake: The liquid stain on Dennis in the restaurant suddenly becomes much smaller when he offers to pay Mac's tab, then gets larger again as he smiles.