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Since release of September 2025 CU for SharePoint Server Subscription Edition we received several reports of application pool worker process crashes with Exception code 0xC0000409 being reported in the event log 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 […]

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Important: If your current farm patch level is September 2025 CU, remove the NT Authoritysystem account from WSS_WPG and IIS_IUSRS local security groups of the SharePoint machines – otherwise installing the SharePoint fixes will fail. For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU Below […]

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Important: If your current farm patch level is September 2025 CU, remove the NT Authority\system account from WSS_WPG and IIS_IUSRS local security groups of the SharePoint machines – otherwise installing the SharePoint fixes will fail. For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU The […]

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Important: If your current farm patch level is September 2025 CU, remove the NT Authority\system account from WSS_WPG and IIS_IUSRS local security groups of the SharePoint machines – otherwise installing the SharePoint fixes will fail. For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU The […]

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Important: If your current farm patch level is September 2025 CU, remove the NT Authoritysystem account from WSS_WPG and IIS_IUSRS local security groups of the SharePoint machines – otherwise installing the SharePoint fixes will fail. For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU Below […]

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Important: If your current farm patch level is September 2025 CU, remove the NT Authority\system account from WSS_WPG and IIS_IUSRS local security groups of the SharePoint machines – otherwise installing the SharePoint fixes will fail. For more details check this article: Trending Issue: SharePoint fixes fail to install after installation of September 2025 CU The […]