Exchange Migrator 2.x
Error: 'Unable to update props [CN=.....DC=com][HR=0x800700b7]'.
This error message can be one of many that occur before Exchange Migrator begins using all of the console machines virtual memory. This is caused by a NULL value being returned when EM is gathering the properties of the mailboxes it is migrating.
To resolve this issue please install Hotfix 27949: