Windows 10 build 16188 (rs prerelease)

Windows 10 build 16188 is the fifth Insider Preview build of Windows 10 Fall Creators Update. This build was released to Windows Insiders in the Fast Ring on 4 May 2017.

Changes

 * Added some new features in Microsoft Edge's PDF reader. Highlights include the ability to fill out PDF based forms, add annotations, added a table of contents button, the ability to rotate documents, and the ability to switch from one-page layouts to two-page layouts, as well as change to page-wise scrolling, useful for longer documents.
 * Added Windows Defender Application Guard. This feature requires the Enterprise SKU and Hyper-V.
 * Updated the icon for the Windows Insider Program section in the Update & security part of the Settings app.
 * Intergrated Cortana's settings into the Settings app.
 * Updated the Magnifier Settings page.
 * Replaced the previous Windows Update dialog with a new interactive toast notification.

Bugs

 * PC reset does not work on non-English versions of this build.
 * If you're using a Surface Pro 3 or Surface 3 device, you can't update to this build unless you remove the SD card.
 * Navigating to Settings, then to Update & security, and then going to the Windows Update section has a chance of crashing the Settings app.
 * Navigating to Settings, then to Personalization, then to the Lock screen section may crash the Settings app.
 * Outlook 2016 may freeze on launch due to an issue where the spam filter gets stuck reading the Outlook Data File and the UI waits indefinitely for it to return.
 * The PC may freeze when you're shutting it down.
 * Sometimes the Start menu can fail to launch, but it launches normally other times.
 * The Settings app can crash on launch if certain display languages are used.