Credential prompt after you rest the mouse pointer over the name of a user in SharePoint Online
Consider the following scenario:
You're using Microsoft Office 2016 Click-to-Run.
You're using an Office 365 Exchange Online mailbox, with Modern Authentication enabled.
In this scenario, you may be prompted for credentials intermittently and multiple times in SharePoint Online. This behavior may start to occur when you browse to a SharePoint Online or OneDrive for Business library, and you rest the mouse pointer on the name of a user (such as the Modified By user).
To work around this issue, disable the NameCtrl Class add-on in Internet Explorer. To do this, following these steps:
Open Internet Explorer, click the Settings icon, and then click Manage add-ons.
Under Add-on Types, select Toolbars and Extensions.
Under Show, select All add-ons.
Under the Microsoft Corporation section, select the NameCtrl Class add-on, and then click Disable.
Microsoft Office Contact Retriever tries to retrieve the contact when you rest the mouse pointer on the name of a user in SharePoint Online or OneDrive for Business. However, the Microsoft Office Contact Retriever doesn't support Modern Authentication.
Still need help? Go to SharePoint Community.