My roommates and I signed what we thought was a 6 month lease, but instead it was dated for 7 months. We all signed the lease, but the property manager did not. That property manager is no longer with the company and there is a new one. Since it did not have the property manager's signature, is it legally binding?

Did you move in? If so and they have a copy of a lease that you all signed for 7 months, then yes you are bound to it.

Did you move in? If so and they have a copy of a lease that you all signed for 7 months, then yes you are bound to it.

Yes we did the we moved in 9/01/12 and is set to end 3/29/13. Sorry if I sound ignorant but I thought both parties had to sign to be legal?

It is not clear unless you are aware of contract law. A contract (and a lease is a contract) requires a consideration on both sides. You signed the lease accepting the terms, and gave a security deposit and/or first months's rent. The property management accepted the lease and handed you the keys. That sealed the contract.

Well there we go, thanks for the help bud

Glad to assist