A new "App Search" field has appeared to the right of the normal Search field. I can't seem to find any information on the articles explaining what this is or how to remove it. The "App Search" field also doesn't do anything. You can't type anything where it says App Search and nothing happens when you click the magnifying glass. A couple of things that have already been attempted:
- restarted Outlook
- restarted computer
- checked on others on different computer (they also have it)
- tried resetting view in settings

Hi, I came across this as I had exactly the same issue but after I removed Office 2019 and installed Office 2021 and installing the latest update, so looked for answers on this forum.
In my case a full shutdown and restart did clear it. However, after completing the restart I noticed that the whole UI had been refreshed to the new look (the one with all the borders etc) and no App Search box. Which leads me to believe this is an experimental UI update for Office 365.
There is a way to block experimental updates from Outlook (and the other Office Apps) which may or may not still work via the Registry.
- Shut down all office apps.
- Start -> Run -> regedit (will require admin account)
- Create a backup of the registry using the Export function (backup the whole lot)
- Navigate to: Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\ExperimentConfigs\ExternalFeatureOverrides Note: you may need to look under Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\15.0 etc for Office 2019
- Click on Outlook (there may only be one entry labelled (default) in the right hand pane.
- Add the following 3 keys (they will have to be added manually) by right clicking in the right hand pane and selecting 'new string value'.
- Microsoft.Office.UXPlatform.FluentSVRefresh
- Microsoft.Office.UXPlatform.FluentSVRibbonOptionsMenu
- Microsoft.Office.UXPlatform.RibbonTouchOptimization
- After creating each of the key, double click on it and set the value to 'false'
-

- You should have some thing like this:

- Not necessary to restart PC (but good practice)
- Restart Outlook
This may or may not work as it is focussed on the ribbon. If it does you can apply the same registry keys to the other office apps.