We have exchange 2010, there are several users, who were migrated from exchange 2003. We encountered several problems with x500 records. We modified x500 records to the right form, but after few weeks wrong x500 records were created again. We find out that this have something common with LegacyExchangeDN. We can see that LegacyExchangeDN is pointed to new "Exchange Administrative group". Could you explain me why new x500 records were created (I think it is somehow synchronized with the LegacyExchangeDN) Do you know what could be responsible for creation of x500 records automatically? Thank you in advance
Most likely the X500 addresses are being created by a Recipient Policy. Check the policies that you have present in your organization - most likely one of them is set to enforce the creation of an X500 address.
However, the legacyExchangeDN will still be present on those accounts.. so if the value that it's being set to is a problem, then you'll need to address that problem directly. Can you clarify on that point?