I have been trying to sort out how to add a shared inbox that I have access to through an Office 365 account (even if through) IMAP and must be doing something wrong. Has anyone had success with this that could point me in the right direction?
I have several shared accounts through IMAP, and someone else at home has a shared Outlook account they access through Mailspring. What specifically is not working? Any error messages?
I’m getting a login credential error so I’m assuming I’m formatting the account details incorrectly.
I have been trying iterations around me@domain.com\shared@domain.com as the user with my account password. I have the correct server information and ports I know, but if you could point me in the direction for how you setup the account name when you added it I would greatly appreciate it.
Ahhhh, Shared Mailboxes is actually a distinct thing. TIL!
I don’t know anything about them. I’ll relay this to @bengotow in hopes he has an answer. There’s often long delays in his response, mind you, as he has very limited time for Mailspring development to begin with.
Thank you! I completely understand about the timing and really appreciate your help!
Do you have updates regarding this topic? 
Any updates regarding this feature? I am also interested in having Mailbox support for shared mailboxes.
I tried to manually “duplicate” an account and modify the configuration but I am getting the following error: “Account is missing required fields:imap_password or refresh_token”
Not the best solution but I assigned a password to the shared mailbox, enabled login for the account, enable IMAP service, and enabled SMPT AUTH. With these settings, you can connect to the shared mailbox using the newly assigned password as if it were a regular account.
Again: not the best practice but it’s just a workaround for the time being.