Microsoft today released Windows 10 Build 15063.994 (10.0.15063.994) to everyone on Creators update (Windows 10 Version 1703). Cumulative update KB4088891 brings this build and is available to install.

There are fixes and security updates for various Windows components. Read the full changelog below. You can check the update availability by going to Settings–>Update & Security–>Windows update–>Check for updates.

Windows 10 Build 15063.994 (KB4088891) Changelog:

Improvements and fixes


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

  • Addresses issue with a GDI handle leak in the Windows Ribbon control.
  • Addresses issue where, during BitLocker decryption or encryption of a drive, files protected with the Encrypting File System (EFS) may become corrupted.
  • Addresses issue where, when an iSCSI request contains an incomplete header in the first packet, iSCSI may not recognize when a request has been sent.
  • Adds support in stornvme for additional SSDs.
  • Addresses issue where the Japanese keyboard layout was not functioning properly during a Remote Assistance session.
  • Addresses rendering issue in Microsoft Edge for PDF documents with backgrounds created using various third-party publishing tools.
  • Addresses issue that decreases the Universal CRT’s performance in the _gcvt and _gcvt_s functions.
  • Addresses issue in which the output to a file or pipe was fully buffered in the Universal CRT for the standard error (STDERR) stream.
  • Addresses issue in the Universal CRT by adding the “x” access mode flag to support the fopen() function.
  • Addresses issue with a race condition in the Universal C Runtime (CRT) that occurs when you update the global locale. The issue corrupts the current locale reference count and triggers a double free condition.

If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.