Are there any tools in SW (or addons) to help diagnose/locate mate loops and other non-best-practices such as those in http://help.solidworks.com/2010/English/SolidWorks/sldworks/LegacyHelp/Sldworks/Assembly2/Best_Practices_for_Mates.htm ? (If not would more expert SW users find this a useful suggestion?)

I've got a complex large assembly that I can't post here. Its a mix of different designers (some files are in chinese) and seems to have been made mainly to produce production drawings. I'm now trying to relax some of the degrees of freedom to visualise the assembly 'working'.

Most of the time the model can be moved by hand and builds fine (no warnings or errors). every now and then (generally on opening the file the next day) either mates break or some or the orientations change. When that happens, Matexpert and other dialogs don't seem to help me find the source(s) of the problems (that must be there). (Somewhat separately motion analysis is also still having problems with the model (there are a lot of redundant mates and it hangs trying to calculate anything)).

I've already deleted mates and recreated them in some higher level sub assemblies which i thought were most likely to be causing problems, wihout getting clearer insight to the source(s) of (remaining) problems. I've got in the order of 20 true degrees of freedom, but lots of bolts, nuts, washers, pins in slots etc in the model - where possible i've got most of these in subassemblies configured as rigid. any other tips for 'debugging' (leading to improved model)?

thanks in advance

(I'm in SW2010, but please mention useful tools in all versions)