When I run setup /prepareAD the "Organisation Preparation" fails, returning the following error message: "The well-known object entry B:32:A7D2016C83F003458132789EEB127B84:CN:Exchange Servers\0ADEL:207f1505-1758-4d1e-822e-0b17754e7240,CN=Deleted Objects,DC=mydomainname,DC=co,DC=uk of the otherWellKnownObjects attribute on container object CN=Configuration,DC=mydomainname,DC=co,DC=uk points to an invalid DN or a deleted object. Please remove the entry and rerun the task." So, back ground info: We have had Exchange 2007 installed as a test but have had to rebuild the server (64bit). The server now has a different name and I'm trying to reinstall Exchange. I've tried to locate the deleted objects in AD with ldp (as described on various pages in technet) but without success. I've also set the tombstone life time to 1 and garbage collection to 1 in an effort to get the deleted objects removed completely in a shorter time period. So far the problem still remains. Is there a sure-fire way of locating the object and removing it completely? Colin

There is nothing so satisfying as solving a problem yourself. If anyone is interested, the problem was that the otherWelKnownObject attribute value was ":\\:" instead of either a GUID or blank. The value could not be removed as it did not appear in the values list. Entering a new blank value setthe valueto <Not Set>. A re-run of setup worked fine and Exchange was able to commence installation.

I'm having the same problem, how were you able to solvethe problem? thanks:

See post http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3562181&SiteID=17&mode=1