April 11, 2017—KB4015551 (Monthly Rollup)

Improvements and fixes

This security update includes improvements and fixes that were a part of update KB4012220 (released March 21, 2017) and also resolves security vulnerabilities in Internet Explorer, Scripting Engine, Hyper-V, Win32K, Adobe Type Manager Font Driver, Microsoft Outlook, Graphics component, Lightweight Directory Access Protocol and Windows OLE. For more information about the security vulnerabilities resolved, please refer to the Security Update Guide.

Known issues in this update

Microsoft is not currently aware of any issues with this update.

How to get this update

This update will be downloaded and installed automatically from Windows Update. To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

• **File information **For a list of the files that are provided in this update, download the file information for update 4015551.

More Information

• The security fixes that are listed in this Security Monthly Quality Rollup 4015551 are also included in April 2017 Security-only Quality Update 4015548, with the exception of security fixes for Internet Explorer, which are instead included in Cumulative Security Update for Internet Explorer KB4014661. Installing either this Security Monthly Quality Rollup or both the Security-only Quality update and the Cumulative Security Update for Internet Explorer will install the security fixes that are listed here. This Security Monthly Quality Rollup also includes improvements and fixes from previous monthly rollups.
• If you use update management processes other than Windows Update and you automatically approve all Security updates classifications for deployment, April 2017 Security Monthly Quality Rollup 4015551, April 2017 Security-only Quality Update 4015548, and Cumulative Security Update for Internet Explorer KB4014661 are deployed. We recommend that you review your update deployment rules to make sure that the desired updates are deployed.