If you have started having difficulty with Microsoft Dynamics CRM or Microsoft Dynamics 365 for Customer Engagement and you are using Internet Explore v11 then you want to make sure you have the latest KBs. The March 20th updates broke a few things, the March 27th updates fixed these.
For Windows 8.1 and 7 SP1 Users
KB4016446 - https://support.microsoft.com/en-us/help/4016446
KB4016446 Download Link - http://www.catalog.update.microsoft.com/search.aspx?q=KB4016446
For Windows 10 users search the catalog for
If you have other Internet Explorer Issues then you might want to walk through this set of Articles.
Internet Explorer: Web application requirements for Microsoft Dynamics 365 https://technet.microsoft.com/en-us/library/hh699710.aspx
Internet Explorer: FAQ for IT Pros https://technet.microsoft.com/itpro/internet-explorer/ie11-faq/faq-for-it-pros-ie11
Microsoft Edge Deployment Guide for IT Pros https://technet.microsoft.com/itpro/microsoft-edge/index
Compatibility Changes in IE 11 https://msdn.microsoft.com/library/bg182625(v=vs.85).aspx