The KB5035849 cumulative update released during today's Patch Tuesday fails to install on Windows 10 and Windows Server systems with 0xd0000034 errors.

According to a wave of reports from administrators and users, KB5035849 will not install when checking online for updates via Windows and Microsoft update servers.

Affected systems include those running Windows Server 2019 or Windows 10 Enterprise LTSC 2019, which have reached their mainstream end-of-support date on January 9 and are under extended support for five more years until January 2029.

"Had the same issue (0xd0000034) with 'Check online for updates', but WSUS versions of these seem to install w/o issue," one admin said.

"Yep - entirely fails to install on every single Server 2019 instance we've got - which is an *awful* lot of instances," another confirmed.

While many customers have already reported that KB5035849 doesn't install on their devices, Microsoft says that it's "not currently aware of any issues with this update."

In today's support document, the company also tagged it as available for installation via Windows Update and Microsoft Update.

Those experiencing these issues can still deploy KB5035849 manually by downloading and installing it from Microsoft's Update Catalog.

"The MSU has not been released for WUD on this KB yet. You can download it from the update catalog," one user said.

However, as Redmond explains, you must first install the KB5005112 August 2021 servicing stack update (SSU) for your operating system before manually deploying the KB5035849 cumulative update.