The KAUST Information Technology Department blog
11 August, 2026
If you use Outlook on a Mac, an important change is coming.
Starting in October 2026, Microsoft's older Legacy Outlook for Mac will no longer work with KAUST Exchange Online mailboxes.
If you already use the current Outlook for Mac, you do not need to do anything.
If you still use Legacy Outlook, we recommend switching now rather than waiting until October. This gives you time to become familiar with the current Outlook and, more importantly, check that the features you rely on work the way you expect.
This is a change being made by Microsoft. Legacy Outlook depends on older Microsoft technology that is also being retired.
Because of this, KAUST IT cannot keep Legacy Outlook working after Microsoft retires the service it depends on. The current Outlook for Mac will become the supported Outlook experience on macOS.
Don't wait until October
For most people, switching should be straightforward. But some advanced Outlook features work differently, have known issues, or are not available. Switching early gives you time to identify anything that affects your work while KAUST IT can still help you explore alternatives or escalate issues to Microsoft.
Already using current Outlook?
No action is required. You are already using the Outlook experience Microsoft will continue to support.
Still using Legacy Outlook?
Switch now and start using the current Outlook for your normal work. Check the features you use regularly rather than waiting until October.
Manage someone else's calendar or mailbox?
Please test your workflow now. Some advanced delegation features have known differences or issues in the current Outlook for Mac.
The current Outlook for Mac supports most everyday email and calendar features. The areas below are the differences we think are most important to know about before you switch.
Manage someone else's calendar? Please spend a few minutes testing.
If you are an executive assistant, secretary, administrator, or anyone who regularly works on behalf of someone else, switching successfully means more than checking that their calendar opens.
Try the tasks you actually perform during a normal day:
Please let KAUST IT know now rather than switching back to Legacy Outlook and waiting until October.
We will first check whether the feature works differently in the current Outlook or whether another supported way of completing the task is available.
We'll investigate
We can check whether the feature has moved or now works differently.
We'll look for an alternative
If Microsoft provides a workaround or another supported method, we'll help you understand it.
We'll escalate where appropriate
Known issues and product limitations affecting KAUST can be raised with Microsoft.
What KAUST IT can and cannot change
The features Microsoft includes, changes, or removes from Outlook are controlled by Microsoft. KAUST IT cannot restore a feature Microsoft has removed or keep Legacy Outlook working after Microsoft retires the services it depends on.
What we can do is help you understand the change, identify the best available alternative, investigate problems, and make sure Microsoft is aware of issues affecting the KAUST community.
If Legacy Outlook works well for you today, it may be tempting to leave everything as it is.
The problem is that Legacy Outlook will not remain an option for your KAUST mailbox once Microsoft's change takes effect.
Switching now gives you time to test without the pressure of an approaching deadline. If everything works, you're ready. If it doesn't, we'd much rather know now.
Need help?
If you're unsure which Outlook you're using, need help switching, or find that something you rely on does not work in the current Outlook for Mac, contact KAUST IT.
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