Installation
Troubleshooting
Legacy mailboxes displayed in Outlook even after permissions removed
2 min
issue after permissions/access to another mailbox (either shared or another user) have been removed and new ones added, the user still sees the "old" list of mailboxes displayed in outlook (2016/o365) solution as part of a migration to exo/office 365, often permissions to mailboxes are updated either because they have to be re applied for technical reasons, or because the customer wants to use the opportunity to review mailbox delegations with both the user and "other" mailbox in the cloud, permissions are applied directly via powershell or ms graph as per standard ms protocols as part of this process, exchange updates the attribute \<msexchdelegatelistbl> on the user's azuread account however this is not written back to the local ad account when outlook opens it looks at this attribute to determine the list of mailboxes that the user has access to, and displays them however in this situation the list is no longer valid the user will not be able to access these mailboxes if they attempt to open them they will receive an error however they will be displayed there are several potential solutions from manually updating the attribute to simply clearing it, neither of which provide a good user experience the ideal solution is to have activate monitor the attribute on the user's azuread account for the updated value (this may take some time due to replication/processing within exo/365), and then copy the value onto the attribute on the local ad account note there is an attribute called \<msexchdelegatelistlink> which can be confused with the correct attribute this is not the attribute that provides outlook with the data for presenting mailboxes