Do you use extensionattributes? We do. Up until yesterday I assumed that extensionattributes 1-15 were one of those little bonuses you get with Exchange that remained exactly as you set them – forever. I have a truckload of scripts that add/change and remove values in extension attributes for all AD account types and everything works perfectly.
Until, that is, you run that destroyer of worlds, 'Disable-distributiongroup'. I was doing some extensive testing on an application that allows people to make modifications to groups. I started by unchecking the mail enabled checkbox (on my application) and it went through and executed 'Disable-distributiongroup'. Just for fun, I tried mail enabling that group again and noticed that another field displayed in my app that came from extensionattribute5 had disappeared from the group object in AD. After troubleshooting, I discovered that the value of extensionattribute5 was indeed cleared by the running of 'Disable-distributiongroup'. Just for fun I then set a value in all 15 extensionattributes and lo and behold, running 'Disable-distributiongroup' cleared all of them!
So the moral of the story is that if you use extensionattributes and expect them to be there after running 'Disable-distributiongroup' then you're in for a surprise!
We run Exchange 2010 Version: 14.03.0248.002 btw.