Forum Discussion
How to stop Outlook365 from auto-discovering previous credentials on a shared mailbox
As part of complying with security best practise we have converted ‘shared’ regular mailboxes to shared mailboxes. A key requirement is to enable shared mailbox to be set as default and to enable mail sent from SM to go to the SM Sent Items folder.
Part of the process is to add the SM under File/Account Settings/Account Settings/New but because these have been used before, the credentials have been stored and auto discovery then prevents the option to ‘Sign in with another account’ on the password pop up… as documented by Microsoft… see section 2d:
These are the things I have tried to:
- Removed any previous ost and auto discovery xml files linked with the converted mailbox
- Disable Auto-Mapping using Exchange Online Powershell
- Cleared Cached Credentials
- Cleared any previously saved identities in the registry
HKEY_CURRENT_USER\Software\Microsoft\Office<version>\Common\Identity - Created New Outlook profile
- Reset AutoDiscover Settings (outlook.exe /resetnavpane)
- Disable AutoDiscovery (reg tweak)
- Disabled Simplified Account Creation (reg hack)
- Checked for Outlook updates
I have proved this works with a MS engineer last night on a fresh laptop account but I really need to fix existing user accounts.
I just can’t seem to be able to add the SM with a users account!
Any magicians out there that can suggest something?
I'm beginning to think this is a bug
AJH2024
The solution has been found thanks to Solomon (one of the best MS engineers I've ever met)...
1. Change password of SM on MS 365 and block sign in
2. Remove the SM account from Outlook
3. Ensure the SM account is not Stored in Settings/Accounts/Access work or school
4. Clear SM details from Credential Manager
5. Goto C:/Users/<username>/AppData/Local/Micorosft/Outlook
Delete any ost and nst files relating to the SM
Delete the Autodiscover.xml files
Delete 'Offline Address Book' folder
In the RoamCache folder - delete all
In the 16 folder - delete all
Zip the MIPSDK folder and then delete the folder
6. Goto C:/Users/<username>/AppData/Local/Micorosft/OneAuth/Accounts
Open files in Notepad and delete any with the SM details
7. Goto C:/Users/<username>/AppData/Local/Micorosft/OneAuth/Blobs
Zip the Blobs folder and then delete the folder
8. Goto C:/Users/<username>/AppData/Local/Micorosft/IdentityCache
Zip the IdentityCache folder and then delete the folder
9. Create new Outlook profile and default it to open, this will include adding the user account
10. Start Outlook > File/Add Account.... add the SM, this time it will allow you to add the credentials of the users account.
AJH2024
The solution has been found thanks to Solomon (one of the best MS engineers I've ever met)...
1. Change password of SM on MS 365 and block sign in
2. Remove the SM account from Outlook
3. Ensure the SM account is not Stored in Settings/Accounts/Access work or school
4. Clear SM details from Credential Manager
5. Goto C:/Users/<username>/AppData/Local/Micorosft/Outlook
Delete any ost and nst files relating to the SM
Delete the Autodiscover.xml files
Delete 'Offline Address Book' folder
In the RoamCache folder - delete all
In the 16 folder - delete all
Zip the MIPSDK folder and then delete the folder
6. Goto C:/Users/<username>/AppData/Local/Micorosft/OneAuth/Accounts
Open files in Notepad and delete any with the SM details
7. Goto C:/Users/<username>/AppData/Local/Micorosft/OneAuth/Blobs
Zip the Blobs folder and then delete the folder
8. Goto C:/Users/<username>/AppData/Local/Micorosft/IdentityCache
Zip the IdentityCache folder and then delete the folder
9. Create new Outlook profile and default it to open, this will include adding the user account
10. Start Outlook > File/Add Account.... add the SM, this time it will allow you to add the credentials of the users account.
