My first thought would be to try adding in contact sets instead of relying on the global contact.
Sometimes contact sets are required in order to restrain the model correctly.
This exact problem has happened to me many time with SW - I have begun to doubt that the powers that be are even trying to solve the issue.
However, there are easy fixes that work very well.
1. If you know which parts in the assembly are not 'bonded' then just bond those two together.
2. If you don't know you can set up bonded contact sets (automatically w/in the assy usually works quite well especially if you have a large assy).
3. If you are importing geometry either from another CAD program or a step file and not dealing with native-built SW parts that could be 'most' of your problem. This is presuming that you at least did a clean-up of the parts for slivers, gaps, etc. (Re-modeling is the time-efficient way of overcoming these type problems in my experience.)
Further, I'd recommend you clean up your model so there are no errors (as shown in the upper window) and everything is properly restrained, no unexpected gaps or interferences.
What is the goal of the simulation?
Is your global contact set to Bonded or No Penetration?
Do you have the check box for incompatible mesh selected?
Depending on the information you're hoping to gain from the simulation you could leave out the pin where the force is being applied and create a split face in the hole of the crank arm to apply the force to and add an equivalent torque as an additional External Load. You would run this simulation only on that individual part file. It would run faster this way if that is the part of concern. There are instances where you may want to use soft springs to stabilize the model but I don't think this is one.