This is an original post from Paul Holmes from Horizons Consulting http://www.hrizns.com
While working on the Exchange 2003 servers, I ran into an interesting issue. After creating a recovery storage group I attempted to add a mailbox store to the RSG. However, this would fail with an LDAP filter error. In working with PSS we discovered that this was being caused by a typo in one of the mailbox store names. Apparently, one store had a missing right parenthesis. According to PSS, the total of left and right parentheses must match but they do not necessarily have to be in any sort of order. After adding the missing parenthesis to the store name it resolved the issue.