Hi @Kenny Stern ,
We have a number of users experiencing this issue
Did it occurred on a normal user mailbox or a shared mailbox? And did it occurred only recently? If so, have you performed any specific operations before?
Are there any users who could search normally in your organization? If so, do they have any differences from these users that couldn't search normally(such as the version of Outlook client or others)? Considering you are using a earlier version of Outlook, it's suggested to first update your Outlook to the latest version to get a better experience.
In order to further confirm if the issue is related to your client or account, it's suggested to log these users that couldn't search normally to other Outlook client to check if the issue has any difference.
If the issue could be reproduced on other client, it may be more related to your account itself instead of Outlook client.
If it could work normally on other client, it may be more related to your client. In order to avoid the interference of other program and Outlook add-ins, it's suggested to close other program and restart your outlook to check if it could work normally(windows + R > type "outlook.exe /safe">enter)
Also, the issue may also occur when your outlook profile is corrupted, it's suggested to create a new Outlook profile and readd your account to check(Control Panel>Mail>Show profiles>Add>readd your account).
Hope that would be helpful to you.
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