Windows 7 KB4099950 fixes NIC settings and IP address issues

Milan Stanojevic
by Milan Stanojevic
Deputy Editor
Affiliate Disclosure


Microsoft provided cumulative Spectre and Meltdown protection with Windows 7 Monthly Rollup KB4088875 and security update KB4088878. However, many users have experienced various issues after installing the respective patches.

As a result, Microsoft rolled out a new update for Windows 7 Service Pack 1 and Windows Server 2008 R2 to fix these problems.

KB4099950 is a maintenance update to fix the problems with the virtual network adapters caused by the security updates of Patch Tuesday in March. The bug was replacing the existing adapter and breaking down network connections as Microsoft said:

A new Ethernet Network Interface Card (NIC) that has default settings may replace the previously existing NIC, causing network issues after you apply this update. Any custom settings on the previous NIC persist in the registry but are unused

Downloading and installing the new update

This update can be downloaded and installed automatically from Windows Update. Alternatively, the standalone package for this update is also available on the Microsoft Update Catalog website.

microsoft updates catalog

Please be aware that if you have installed one of the above-mentioned updates and then manually restored the adapters, you have to uninstall the update. Afterward, install the new update KB4099950 and then KB408875 or KB408878.

Microsoft is not aware of any issues affecting this update, so the install process should go smoothly and you shouldn’t encounter any issues afterwards either.

Have you installed KB4099950 on your Windows 7 computer yet? Tell us more about your experience in the comments below.


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1. I have downloaded the April 2018 updates but did not find KB4099950 among them ? Although I read that its available through WSUS but I cant find it ? is it part of monthly roll up ?
2. If I have fixed manually some of Server 2008 NIC issue, do I still need to update those servers with this fix or I can leave them alone and apply it to the only one where KB4088875 & KB4088878 have not been yet applied or its important to go through the “uninstall ” and reinstall cycle.

the text “if you have installed one of the above-mentioned updates and then manually restored the adapters, you have to uninstall the update” seems pretty confusing to me. Which “previous updates” and which “update” are you reffering to? I have problems with all win7 pc’s since early april, They say that our network printers are offline.until i mess up with their fixed IP. This solutions lasts until next reboot.

Some of them have already KB4099950 installed but doesn’t seem to fix the problem. What should I do? I can’t find any KB4088875 or KB4088878 installed so i can roll them back.