I was working a structural floor assembly, I had some angles that where patterned on one side of the tube mirrored to the other side along with some other parts.  I had to edit this assembly and I took out one of the angles, nothing was tied to this angle at all, so it should have been a simple fix and go.. But where is what happened.

When I got ouf of the pattern, everything that was mirror and pattern in the design tree disapeared, I then click on the next one below to edit it to see what had happened, changing nothing but just getting out of edit mode fixed the patterns and mates one by one as I went.  But the problem lies with things that where mated to the things that where mirrored, now I have a ton of broken mates with missing faces, it's like everyting that was mirrored was coded as a new part.

The sad thing is this happened to a co worker of mine as well, at first I just thought him being a new SolidWorks user he just made a mistake but even then I thought there is no way he could have messed the model up this bad, now I know for sure it wasn't him.

Has anyone else seen this or something similiar? Hope what I described made sense...

I am using SW 2014sp2