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AJH2024's avatar
AJH2024
Copper Contributor
Oct 11, 2024
Solved

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's avatar
    AJH2024
    Oct 14, 2024

    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's avatar
AJH2024
Copper Contributor
Oct 14, 2024

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.

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