Drawing Refs not updating

Hi'

I'm having a probleb changing a drawings referenced model.

I have an existing drawing which references an assembly.

I have replaced the original referenced assembly with a new assembly with the same file name. When I open the drawing the views in my drawing show no geometry just a bounding box and X from corner to corner. If I right click on a view I get the option to open the correct model, but the view properties do not show the reference model name and are greyed out.

I have recently upgraded to SW2012 sp4 from sw2011.

Has anyone got any ideas?

Thanks

Craig

SolidworksDrawings And Detailing