Hello I have been noticing in my assemblies that mates will be there when I am working on it and save but when I open it up again some mates are suppressed and I never suppressed them.  Solidworks just seems to be automatically suppressing mates.  I am working with multiple configurations I am not sure if that makes a difference or not.  So I have to go back though and unsuppress them.  But I have been noticing that Solidworks will do it in some assemblies and not in others.  And looking in the configurations properties they are the same even for the assemblies that Solidworks has not suppressed mates automatically.  Even in the default assembly are there some mates that are automatically suppressing.  These are fairly large assemblies and I am working with 2015 but I am just wondering if there is any reason for this and if you guys know of ways that I can avoid this so that if I have to make a change I do not have to down into the tree and unsuppres a lot of mates, because it is not just suppressing a few but a LOT, to make sure my assembly does not fall apart.  It does not seem to matter if the configurations manager properties has the "Suppress new features and mates" checked or unchecked.  Sometimes with it checked the mates are still not suppressing and when the box is checked a lot of the mates are still suppressing.

Thank you guys in advance for your advice on this I do not know if it is a setting in Solidworks or if there is a way to avoid this issue I am having.