There are no new extensions, just the ones she needs, which I also tried to disable for testing, but it didn't solve the issue. In previous versions of Outlook, the Search tab was always visible on the ribbon. If you use Microsoft 365 (M365) or Office 365 (O365), you should have the new Search box. Fortunately, there’s a way you can make that tab stay put permanently. In addition, it contains 1 documented non-security fix for Outlook Current Version. It contains 10 security updates for Excel (6), Visio (2), Word (1), and Office (1). You can also quickly access the Advanced Find command by pressing Ctrl + Shift + F keys. A new rollup update has been made available for all Click-to-Run installations of Outlook 2016, Outlook 2019, Outlook 2021 and Outlook as part of a Microsoft 365 subscription. I'm sure it's local to her account because: To recover from this scenario, make sure you have at least 1 account configured in Outlook. The only downside is the Search tab is now hidden until you click in the Search box. Go to Options group under Search Tab Click the Search Tools button In the drop down list, click the Advanced Find command item. Running Outlook with /cleanschedplus, /cleansharing, etc. Running Outlook with /cleanfreebusy which doesn't work on 365 Reinstalling Office completely with no luck. So basically the behavior is random as to which person's calendar is unavailable. If she closes Outlook and creates a new meeting with those same participants, then the one who was greyed out previously will be available now and second will not.

The weird thing is, if for example she adds 2 people to that meeting, one will be greyed our and the other wouldn't. It's been that way since forever and now for some reason it doesn't work for a certain VP in my company. So in my org, whenever you're scheduling a meeting, you are able to see the participants' mettings for that time frame. Hopefully the answer will come from here.

Outlook search tools greyed out