Which Exchange update is right for me to install? Both? [Update Rollup for Exchange 2000 KB870540)] or [Exchange 2000 Post-Service Pack 3 (SP3) Rollup Patch 6487.1] We are running Exchange 2000 SP3(Version 6.0 [Build 6249.4: Service Pack 3]) on a windows 2000 serverand I was looking at the updates available for Exchange and found two that seemed to apply, but I'm confused as to which one I should apply, or if I should apply them both. One is [Exchange 2000 Post-Service Pack 3 (SP3) Rollup Patch 6487.1], which is 32mgs in size and was released 8/27/03 The other is [Update Rollup for Exchange 2000 KB870540)], which is 14.6mgs in size and was released 8/16/04 Both state in their overview the equivalent of "Fix problems found in Exchange since Exchange SP3 was released". Now my first assumption would be to just install the newest one, [Update Rollup for Exchange 2000 KB870540)], which is 14.6mgs in size and was released 8/16/04, but the size of the file is actually smaller than the [Exchange 2000 Post-Service Pack 3 (SP3) Rollup Patch 6487.1] update 32mgs, which makes me think that the *newest* update doesn't have all the updates. So now I'm thinking I need to apply them both and apply the oldest patch first with the newest patch second. Does this sound reasonable? Any thoughts or suggestions?

I would typically install the latest. You may want to go to Windows Update from the server and upgrade to Microsoft Update ( link on the right hand side of the menu). Then let it tell you what Exchange patches you need.