For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU
The product group released the February 2026 Cumulative Update for SharePoint Server 2016 product family.
This CU also includes Feature Pack 1 which was released with December 2016 CU and Feature Pack 2 which was released with September 2017 CU.
The KB articles for February 2026 CU should be available at the following locations in a couple of hours:
- KB 5002841 – February 2026 Update for SharePoint Server 2016 (language independent)
This is also a security update! - KB 5002840 – February 2026 Update for SharePoint Server 2016 (language dependent)
This is also a security update!
The downloads for February 2026 CU are available through the following links:
- Download February 2026 Update for SharePoint Server 2016 (language independent)
This is also a security update! - Download February 2026 Update for SharePoint Server 2016 (language dependent)
This is also a security update!
Important: It is required to install both fixes (language dependent and independent) to fully patch a SharePoint server. This applies also to servers which do not have language packs installed. The reason is that each SharePoint installation includes a language dependent component together with a language independent component. If additional language packs are added later (only) the language dependent fix has to be applied again.
It is irrelevant which language you pick on the drop down in download center. Even the language dependent fixes are all in the same package for all languages.
After installing the fixes you need to run the SharePoint 2016 Products Configuration Wizard on each machine in the farm. If you prefer to run the command line version psconfig.exe ensure to have a look here for the correct options.
SharePoint 2016 February 2026 CU Build Numbers:
Language independent fix: 16.0.5539.1002
Language dependent fix: 16.0.5539.1002
To understand the different version numbers please have a look at my article which explains the different SharePoint build numbers.
Please ensure to have a look at the SharePoint Patching Best Practices before applying new fixes.
Related Links:
- Technet: Updated Product Servicing Policy for SharePoint Server 2016
- Blog: SharePoint Patching Best Practices
- Blog: Common Question: What is the difference between a PU, a CU and a COD?
- Blog: SharePoint Patching demystified
- Blog: Why I prefer PSCONFIGUI.EXE over PSCONFIG.EXE
- Technet: Update Center for Microsoft Office, Office Servers, and Related Products
- Blog: SharePoint Server 2016 Patch Build Numbers Powershell Module
- Blog: SharePoint Server 2016 Zero-Downtime Patching Demystified
- Blog: SharePoint does not have a build version. Full Stop.
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I ran the updates for February 2026 (SPWM, KB5002840, and KB5002841) in my Dev SharePoint 2016 environment that has a single WFE, rebooting after every install and then I ran the SPCONFIG Wizard twice, rebooting after each time. The Database version still says 16.0.5539.1001. SharePoint is functional and my test workflows are working properly. What would cause the database version to not increment to 16.0.5539.1002?
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Hi David,
see here for a detailed explanation:
https://blog.stefan-gossner.com/2016/08/23/sharepoint-does-not-have-a-build-version-full-stop/
Cheers,
Stefan
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Hi Stefan!
We are on SP2016 and have issues with the new Machine Key rotation mechanism since applying the Nov 2025 CU. (We did not have Sep CU nor Oct CU’s installed.)
We get viewstate errors in forms: when creating new document libraries and editing document properties etc.
From the ULS:
System.Web.UI.ViewStateException: Invalid viewstate
System.Web.HttpException: Validation of viewstate MAC failed (AutoGenerate cannot be used in a cluster)
We have a Microsoft case open. The support has asked us to run Update-SPMachineKey in a few different ways, to ensure that the machine key is “deployed farm-wide”. It doesn’t help. We have also rebuilt the configuration caches and run IISReset. No improvement there either. Now they tell us to install Feb 2026 CU to see if it helps. I’m not so sure…
The issues above are in our acceptance environment, and it prevents us to install new CU:s in production. We just want to have a secure and updated SP2016 environment while we put all our focus on SP SE migration.
Would you have time to look at our case?
Thank you and all the best,
Will
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Hi Will,
since September 2025 CU the machine keys in the web.config are no longer used. Instead the machine keys are stored in the configuration database.
Update-SPMachineKey is an old CmdLet which was useful before September 2025 CU as it ONLY replicates the machine keys to the web.config – which is no longer used. So this CmdLet will not do anything useful after September 2025 CU.
Set-SPMachineKey is a CmdLet which can still be used to set dedicated machine keys – but only if February 2026 CU is installed as there was a problem in this CmdLet which prevented setting the machine keys in the configuration database.
My suggestion would be to pass this information to the owner of your support case. He can ping me to discuss the case.
Cheers,
Stefan
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Hi Will,
do you have a solution for this problem yet? Unfortunately, we only figured out how the update was installed in production.
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After applying february CU 2026 Access web app site search not working
Checked January CU 2026 also not working
Checked december CU 2025 is working fine
Below is the error message
Error
An error has occurred.
Press Escape to cancel.
Click here to try again.
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Hi Narayana,
I would suggest to open a support case with Microsoft to ensure this is properly investigated.
Cheers,
Stefan
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If I have not installed patch level is September 2025 CU, do I still have to remove NT Authority\system account from WSS_WPG and IIS_IUSRS from the indicated groups?Thanks
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Hi Vincenzo,
no – if September 2025 CU was skipped this step is not required.
Cheers,
Stefan