MSMQ and Windows Service not receiving messages even though queue has messages

Win 7, MSMQ, Windows Service.

I check the开发者_运维知识库 queue in computer management and messages there.

When i run the service by calling it from Main ie a hack to allow debugging it works fine.

But When I run the windows service as a service starting from comp management the queue is not receving any messages.

Any ideas, could it be permissions??