Some devices may hang or freeze when using certain apps, such as “Hey Cortana” or Chrome, after installing the Windows 10 April 2018 Update

Microsoft is aware that some devices running the Windows 10 April 2018 Update (version 1803) may hang or freeze when using certain apps, such as “Hey Cortana” or Chrome. 

 If your device freezes when using an app, try one of the following steps to recover Windows without needing to restart:

1. Try a Windows key sequence to wake the screen.  If you have a keyboard connected, simultaneously press the Windows logo key + Ctrl + Shift + B. If you’re on a tablet, simultaneously press both the volume-up and volume-down buttons, three times within 2 seconds.  If Windows is responsive, a short beep will sound and the screen will blink or dim while Windows attempts to refresh the screen.
2. If you’re using a laptop, close and open the laptop lid.

Microsoft is working on a solution with the goal of including it in the next regular monthly update, currently targeted for a release date of May 8, 2018.  

Update (5/8/18):  A solution was included in the May 8th, 2018 cumulative update (KB4103721).  Windows Update will automatically download and install the solution.  To check for updates now, select the Start button, and then go to Settings > Update & security > Windows Update, and select Check for updates.  If your system still experiences performance problems after installing the latest updates, you may be experiencing a different issue.  Please describe your issue in another thread or by using the Feedback Hub.