Update KB4099950 for Windows 7/Server 2008 R2

[German]Microsoft has surprisingly released update KB4099950 for Windows 7 SP1. It is a maintenance update to fix the problems with the virtual network adapters (NIC problem) caused by the KB4088875 and KB4088878 security updates of March 13, 2018.


Some Background details

The security updates KB4088875 and KB4088878 of March 13, 2018 cause network problems with virtual network adapters. They lose their static IP address and are converted to DHCP address assignment. I reported in detail about this problem and possible workarounds in the article Network issues with Updates KB4088875 / KB4088878.

Update KB4099950 fixes NIC issue

On March 30, 2018, Microsoft released Update KB4099950 for Windows 7 SP1 and Windows Server 2008 R2. Microsoft writes about this:

This update addresses issues introduced in KB4088875 and KB4088878 for Windows 7 Service Pack 1 (SP1) and Windows Server 2008 R2 SP1 where a new Ethernet Network Interface Card (NIC) with default settings may replace the previously existing NIC, causing network issues. Also addressed, is an issue where static IP address setting are lost after applying the update. These symptoms may be seen on physical computers and virtual computers running VMWare.

Microsoft states that there are currently no known issues related to this update. The memory leak that the March 13 updates causes on the SMB server will not be corrected. The same applies to the blue screens that can appear.

The update is distributed via Windows Update, but can also be downloaded from the Microsoft Update Catalog. At this point, I would like to mention that the update is not be distributed via WSUS.

Incomplete documentation?

Microsoft also specifies that update KB4099950 must be installed before KB408875 or KB408878. This means: If you have installed the above updates and then manually restored the adapters, you have to uninstall the update. Then install update KB4099950 and then KB408875 or KB408878, MVP colleague Susan Bradley has similar thoughts.


At reddit.com someone took a look into that update package. Finally, the update applies the PCIClearStaleCache.exe file. This cleans up the adapter entries within the cache that lead to the error. However, Microsoft had published a VBScript correction script for this (see Network issues with Updates KB4088875 / KB4088878). If you have corrected the adapter error with the VBScript program, you can ignore the update KB4099950 imho.

Similar article
Security Updates for Windows 7/8.1 (March 13, 2018)
Network issues with Updates KB4088875 / KB4088878

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4 Responses to Update KB4099950 for Windows 7/Server 2008 R2

  1. amanda says:

    i have a question regarding the kb4099950 update, does it require you to restart your computer? just a yes or no answer as im personally getting tired of that everytime i install any update, thanks!

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