Trending Issue

We have received multiple reports indicating that SharePoint 2010–style workflows are failing after installing the June 2026 Cumulative Update (CU). Symptoms The issue is typically reflected in the ULS logs with entries similar to the following: w3wp.exe (0xXXXX)   SharePoint Foundation   Legacy Workflow Infrastructure   4letu   High   Block the namespace: clr-namespace:System.CodeDom;Assembly=System, Version=4.0.0.0, […]

In recent days we have seen several support cases where Kerberos authentication in SharePoint suddenly starts to fail. In the SharePoint ULS logs you may see errors such as: System.ServiceModel.Security.SecurityNegotiationException: A call to SSPI failed System.Security.Authentication.AuthenticationException: A call to SSPI failed System.ComponentModel.Win32Exception: The encryption type requested is not supported by the KDC Cause Starting with […]

Trending Issue: SPSE - Configuration Wizard will fail for upgrades from January 2026 CU to March 2026 CU

Important: Microsoft Support has received guidance from engineering on how to resolve this issue for affected customers. Customers who installed the March 2026 CU on top of the January 2026 CU and are now experiencing the situation described below are advised to open a support ticket with Microsoft to receive assistance in resolving the issue. […]

To enhance security a new Exploit Protection Setting was added to Windows when installing September 2025 CU for SharePoint Server Subscription Edition. This setting works as expected on Windows Server 2022 but caused the SharePoint Administration Service to fail on Windows Server 2025. Reference Trending Issue: SPAdminV4 fails to start on Windows Server 2025 after […]

September 2025 CU for SharePoint Server Subscription Edition included an security enhancement for the encryption algorithm used by the secure store service to save credentials. As a side effect credentials stored with the old algorithm could no longer be decrypted. When trying to edit an existing target application or when trying to add/update credentials the […]

A race condition in SharePoint Server can lead to application pool worker process crashes with a combination of the following Exception codes 0xC06D007E and 0xE0434352: Faulting application name: w3wp.exe, version: 10.0.20348.1, time stamp: 0xcfdb13d8 Faulting module name: KERNELBASE.dll, version: 10.0.20348.4294, time stamp: 0x689cd397 Exception code: 0xc06d007e Fault offset: 0x0000000000041b39 Faulting process id: 0x32fc Faulting application […]

After September 2025 CU for SharePoint Server Subscription Edition application pool worker process might crash with Exception code 0xC0000409. Event log will contain entries similar to this: Faulting application name: w3wp.exe, version: 10.0.17763.1, time stamp: 0xcfdb13d8 Faulting module name: owssvr.dll, version: 16.0.19127.20100, time stamp: 0x689cd397 Exception code: 0xc0000409 Fault offset: 0x000000000033b39b Faulting process id: 0x32fc […]

To enhance security a new Exploit Protection Setting was added to Windows when installing September 2025 CU. This adds several protections to OWSTIMER.EXE including an option that prevents creating child processes. SharePoint 2010 workflows require the workflow definition to be compiled using the CSC.EXE compiler – and this fails due to this Exploit Protection setting. […]

In the last couple of weeks we have received several reports of for SharePoint Server Subscription Edition application pool worker process crashes with a combination of the following Exception codes 0xC06D007E and 0xE0434352 being reported in the event log similar to these: Faulting application name: w3wp.exe, version: 10.0.20348.1, time stamp: 0xcfdb13d8 Faulting module name: KERNELBASE.dll, […]