Ondrej Žilinec – IT Blog

Today one customer sent me an e-mail with a following problem. They wanted to use e-mail address microsoft@DOMAIN.TLD, but when they assigned this e-mail address to someone they received error that e-mail address is already in use.

So hunting for a bad guy started 🙂 After couple LDAP queries I found out that e-mail address microsoft@DOMAIN.TLD is assigned to System Public Folder located at NON_IPM_SUBTREE\\schema-root\\microsoft. This public folder was mail enabled and question is why this System Public Folders exists and if it needs to be mail-enabled.

Regarding official documentation about Public Folders for Exchange 2010 Exchange uses following system public folders:

• EFORMS REGISTRY
• Events Root
• Offline Address Book
• Schedule + Free Busy
• OWAScratchPad
• StoreEvents
• Other folders <- this one is very nice 🙂

So now I don’t know if public folders under “schema-root” is used or not by Exchange 2010. These system public folders are not designed to be mail-enabled to work properly. There are not send any e-mail, they are used mostly to store system wide information – look for a description of mentioned folders on Microsoft site.

I also compared three Exchange 2010 organizations. One was  upgraded from Exchange 5.5 -> Exchange 2003 -> Exchange 2010, one was upgrade from Exchange 2003 -> Exchange 2010 and last was clean installation of Exchange 2010. On all we had “schema-root” directory, but on clean installation System Public Directory was not mail-enabled. On both upgraded Exchange organizations System Public Folderswere mail-enabled. It looks that mail-enabled System Public Folders are just some left-overs from upgrades.

So IMHO it is best to left System Public Folders in Exchange organization (do not delete them) and disable mail-enabled attribute on these System Public Folders.