The Manager and the Salesman - S6-E15
Continuity mistake: When Michael enters the room he messes with Jim's hair and Jim's hair is noticeably different, however a few different camera angles later Jim's hair is back to normal even though he couldn't have possibly had time to touch it. (00:09:10 - 00:09:50)
Suggested correction: Michael didn't establish the contract with Hammer-mill. Rather, he locked them up as an exclusive supplier. It's unknown if they were already selling the products to Dunder Mifflin alongside Staples and Office Max.
Wrong, Josh says they cannot sell Hammer-mill products as they are exclusive to Staples so therefore they wouldn't have been able to sell there products alongside as mentioned before until Michael made them an exclusive to them solely, Dunder Mifflin. Therefore the original mistake stands true.