Windows 10 build 16188 (rs prerelease)

Windows 10 build 16188 (rs_prerelease) 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.