The issue can be caused by one of the following reasons:
1) Source mailboxes added to MAGE collections before installing MMEX 8.13 Public Update 20161024EX had duplicate folders or subfolders
2) Duplicate folders or subfolders appeared in source mailboxes added to MAGE collections after installing MMEX 8.13 Public Update 20161024EX
The issues can occur if any of the below listed type of duplicate folders or subfolders is found in the source mailbox:
- Source mailbox contains duplicate folders. (Folders having the same name.) One of these folders being the default well-known folder, like Contacts, Calendar, etc. another one being a non-default folder with exactly the same name.
- Source mailbox contains folders of the same folder class in different languages, like both Agenda and Calendar, where Agenda being a default folder and Calendar being its non-default duplicate in English.
- Source mailbox contains duplicate subfolders of any of the default folders, for example, two subfolders with the same name under Inbox, Sent Items, Calendar, etc. folder.
- Source mailbox contains two or more folders having the same name and different index, for example, Calendar and Calendar1, Calendar2. etc.
