I have recently had a problem with our Sharepoint Service after our content\ndatabase was disconnected and then re-connected. We encountered problems\nlogging on untill we re-imported the user profile. Our sharepoint developers\ntried to blame the situation on all the user object sid's in AD being\nchanged, which I don't believe. I am a newbie and so I would like to ask\nunder what circumstances does user object sid's change. I read the Technet\narticle SID vs GUID. This article tells me that SID's will only change if the\nobject moves domain. Can an expert tell conclusively how or when SID's change\nplease. I can't belive that AD would change all user object sid's enmasse.