We have noticed that some of our users are getting the below error:
"The Microsoft Exchange Administrator has made a change that requires you quit and restart Outlook"
No Change has been done from our side and also these mailboxes have been migrated long back to Exchange 2010.
On researching we came to know that if Public folder server ROLE resides on CAS servers (but not on all CAS servers that are part of cas array) this problem could arise, In our environment we had two CAS servers that also hold Public folder server role.
Therefore we decided to move public folder ROLE out of CAS, I will cover the process of moving public folder Role to different server in the later blog post.