Since I upgraded from SW2009 to SW2010 the other day I have noticed that 2010 does not like to perform symmetric mates. Both in mates I am trying to create in new assemblies created in 2010 as well as retaining the mates in assemblies that were in 2009 format that got converted to 2010 format. In addition, when I try performing, or fixing, those symmetric mates my memory usage skyrockets from the usual 700 Mb or so to about 6.5Gb (I have 8 total) and freezes my system up. I am running on win xp 64 and SW2010 sp0. Anyone encountered this problem or know of a fix?