Exchange 2010 uninstall: This computer is responsible for expanding the membership of 1 distribution group(s).  These must be reassigned to another server before Setup can continue.

Issue

When removing an Exchange 2010 server from an organisation I was faced with the following error.

This computer is responsible for expanding the membership of 1 distribution group(s).  These must be reassigned to another server before Setup can continue.

There are no Dynamic Distribution Groups in this organisation, confirmed by running Get-DynamicDistributionGroup.

Resolution

Using ADSIEdit, connect to the Configuration naming content.

Navigate to the Servers container.

1. CN=Services
2. CN=Microsoft Exchange
3. CN=X500 (the name of the Exchange Organization)
4. CN=Administrative Groups
5. CN=Exchange Administrative Group (FYDIBOHF23SPDLT)
6. CN=Servers

Right click on the relevant Exchange Server (e.g. CN=X500EX01) and edit the properties. 

Find the legacyExchangeDN attribute, edit it.

Clear the legacyExchangeDN.

Set the value to be the name of the Exchange server (e.g. X500EX01).

Apply the change.  Retry the uninstall & this time it should be successful.