May 10, 2016 — KB3156421 (OS Build 10586.318)

This update includes quality improvements and security fixes. No new operating system features are being introduced in this update. Key changes include:

• Improved reliability in a number of areas including Cortana, Bluetooth, Shell, Internet Explorer  11, Microsoft Edge , Miracast, and USB.

• Fixed memory leak that occurs when opening a portable document format (PDF) form multiple times.

• Fixed issues with text alignment for right to left languages in Internet Explorer  11 and Microsoft Edge .

• Fixed issue that affected Bluetooth function when a PC resumes from sleep.

• Fixed issue where user accounts weren't locked out after a number of failed sign in attempts.

• Fixed issue with revised daylight saving time.

• Fixed issue that sometimes corrupts CompactFlash cards inserted into a card reader.

• Fixed issue that caused recorded video to be lost when answering an incoming call on some phones.

• Fixed issue that could result in unexpected battery drain while the phone screen is off.

• Fixed additional security issues with kernel mode drivers, remote procedure calls, the Microsoft Graphics Component, Internet Explorer  11, Microsoft Edge , Windows Shell, Windows Journal, Virtual Secure Mode, Schannel, and Jscript.

For more info about the security fixes in this update and a complete list of affected files, see KB3156421.