O365 Shared Mailbox Permissions Reset for Outlook


The issue was resolved (with Microsoft support help) by re-applying Full Access permissions and removing shared mailbox Outlook auto-mapping for the affected users and then adding the shared mailbox manually in Outlook. Re-applying permission via Office 365 admin center didn’t have any effect.

  • Run: Remove-MailboxPermission -Identity shared_mailbox@domain.com -User user@domain.com -AccessRights FullAccess
  • Run: Add-MailboxPermission -Identity shared_mailbox@domain.com  -User user@domain.com  -AccessRights FullAccess -AutoMapping:$false
  • -AutoMapping:$false disables shared mailbox auto-mapping to users’ Outlook profiles.
  • Wait 30-60 minutes for changes to propagate until shared mailbox disappear from users’ Outlook.
  • Manually add shared mailbox to users’ Outlook: File > Account Settings > Change > More Settings > Advanced > Open these additional mailboxes.
  • Try sending email as the shared mailbox by selecting From: address from Online Global Address List (to prevent caching issues).

RDP GPU Rendering

Local Group Policy Editor

Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Remote Session Environment > RemoteFX for Windows Server

Configure RemoteFX  – Enabled
Optimize visual experience when using RemoteFX  – Enabled
Optimize visual experience for Remote Desktop Service Session – Enabled

Use the hardware default graphics adapter for all Remote Desktop Services Sessions  – Enabled
Configure compression for RemoteFX data – Enabled
Use WDDM graphics display driver for Remote Desktop Connections – Disabled

Add simple USB in addition to TPM for Bitlocker Boot

Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives
Require Additional Authentication at startup
Enable then Configure TPM Startup Key
Require Startup Key With TPM
manage-bde -protectors -add c: -TPMAndStartupKey [USB DRIVE LETTER]
manage-bde -status

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