From Cork to Toronto

 I recently updated the ADK on my SCCM server to current, but the ADK version in SCCM (Boot Images, Upgrade Distribution Points) remained stubbornly at 10.0.19041 and I could not access the Drivers tab on my boot image (which is what happens when your image and your reported ADK don't match). Various repairs, reboots and general hacking and slashing came to nought. What did work in the end was running Start, Microsoft Deployment Toolkit, Configure ConfigMgr Integration and take the default (for me) option to remove the MDT extensions (console extensions only). After running that, the ADK version matched up.

 A couple of solutions which are off the well beaten track: 1. You are in a hybrid environment with an on-premises mailbox but an E3/E5 license applied to your user. Exchange Online spontaneously creates a mailbox. (Workaround for this is to remove the Exchange Online sublicence along with the licenses which depend on it - you just have to remember you did that when you migrate to EXO down the road...) 2. You have an old group policy or settings reg file which you think is aligned with MS365 norms but contains the following key - delete it, or change it to Delete in the Group Policy Preferences if it is a wider issue. Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Exchange DWORD MapiHttpDisabled 1 https://learn.microsoft.com/en-us/outlook/troubleshoot/connectivity/outlook-not-connect-exchange-use-mapi-over-http