Distribution Groups - The properties on this object have invalid data.

I am in the process of carrying out another Exchange 2003 to Exchange 2010 migration for a customer with 800 users.  On the Exchange 2010 server, when attempting to open the properties of a distribution group which was created on Exchange 2003, the following message appears.

"The properties on this object have invalid data. If you click OK, the default values will be used instead and will be saved if you do not change them before hitting Apply or OK on the properties page. If you click cancel, the object will be displayed read-only and corrupted values will be retained."

This message can appear in a number of circumstances for any corrupt information on an Exchange 2010 distribution group.  To compare what is corrupt a trick is to do this:

1. Create a new distribution group on Exchange 2010
2. Look at the properties of the distribution group by typing Get-DistributionGroup "New Distribution Group" | fl
3. Compare this against the properties of the bad distribution group Get-DistributionGroup "Bad Distribution Group" | fl
4. Fix whatever invalid information exists on the bad distribution group.

In my case, the Distribution Group had spaces in the Alias.  The alias attribute must not contain spaces, after removing the spaces the error now longer displayed.