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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 mai...
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.
