KB5000803 Windows 10 1607 Build 14393.4283

March 2021 Security patch for Windows 10 version 1607 is now available for download at Windows update. Before applying the KB5000803 cumulative update, make sure to first download and install the recent servicng stack i.e. KB5001078. Ensuring this will make your PC compatible with the latest security patch and also the update process completes without getting into any error. 

You may get this security patch either via Windows Update, Update Catalog, or through WSUS. Let’s explore the key highlights of Build 14393.4283 –


KB5000803 Changelog

Below are the key changes that will come into effect after installing this patch to Windows 10 version 1607 –

  • Increases the OS Build number to 14393.4283.
  • Upgrades the security of Microsoft Office Products and while performing basic operations on Windows 10.
  • Improves the security of the following –

Windows Shell, Windows User Account Control (UAC), Windows Fundamentals, Windows Core Networking, Windows Hybrid Cloud Networking, Windows Kernel, Windows Virtualization, the Microsoft Graphics Component, Internet Explorer, Microsoft Edge Legacy, and Windows Media.

  • Disables the token binding feature while using Windows Internet (WinINet).
  • No heap leak issue when you change the security settings on WMI namespace permissions.
  • Resolves the extra dereferencing issue that is known to stop a running server. 
  • Addresses an issue wherein MIT realm fails to obtain a Kerberos service ticket from Active Directory domain controllers (DC). 
  • Works upon an elevation of privilege security vulnerability documented in CVE-2021-1640 related to print jobs submitted to “FILE:” ports.
  • Improves the overall reliability of the Remote Desktop apps.
  • KB5000803 fixes a stop error 0x0000007E that occur while using nfssvr.sys on servers running the Network File System (NFS) service.
  • Adds a new dfslogkey to Windows 10 version 1607 as described below –


In this, the RootShareAcquireSuccessEvent field has the following possible values –

    • Default value = 1; enables the log.
    • Value other than 1; disables the log.

Note: If this key doesn’t exist prior to installing this build update, it will be created automatically. To make any changes to the dfslog/RootShareAcquireSuccessEvent inside the registry, you must restart the DFSN service. 

  • No more increase in network traffic when you go for a Windows 10 update. Such increase was previously noted while using an authenticated user proxy as the fallback method. 

Known Issues on KB5000803 

No new bugs appear on Windows 10 version 1607 after applying this update. However, the error – “2245 (NERR_PasswordTooShort” still occurs if you have configured the “Minimum Password Length” group policy to use 14 or more characters. 

How to Get this Update

You may get the KB5000803 security-patch via either of the following channels –

Before applying this cumulative update, make sure to first download and install the recent servicing stack update i.e. KB5001078 on your device.

  1. Windows Update: Go to Settings > Update & Security > Windows Update, and hit Check for updates.
  2. Microsoft Update Catalog: Get the standalone package by visiting the official site. Just make sure to download the file that well-matches your system configuration. 
  3. Windows Server Update Services: To get the latest cumulative update via WSUS, configure the Products and Classifications as follows –
    • Product: Windows 10
    • Classification: Security Updates


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