[German]Users of the virtualization platform Proxmox and KVM/QEMU get BlueScreens on virtualized Windows VMs as soon as they install the June 2025 updates. It affects (Proxmox) hosts with AMD CPUs (Ryzen & Epyc). And I got reports, that Linux KVM / QEMU is also affected with it's Windows VMs. The error is known and there is also a workaround.
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Windows June 2025 Updates
On June 10, 2025, Microsoft released numerous security updates for the Windows versions that are still supported. I listed these for Windows clients in the blog post Patchday: Windows 10/11 Updates (June 10, 2025). For Windows 11 24H2, there was also the out-of-band update, which was mentioned in the articleWindows 11 24H2: Out-of-Band Update KB5063060. The updates for the servers are described in the article Patchday: Windows Server-Updates (June 10, 2025). All security updates close serious vulnerabilities, which I have covered in the article Microsoft Security Update Summary (June 10, 2025) and in other articles linked at the end of the article
Reader report on the Proxmox BSOD problem
German blog reader Christof P. had already contacted me by e-mail on June 12, 2025 because he had run into a problem and did not seem to be the only one affected. He wrote that the latest updates for Windows 11 and Server 2025 were causing massive problems in virtual machines (VMs) when they were running under Proxmox.
After the update installation and reboot, the VMs crash with a blue screen (BSOD) "Unsupported Processor". This affects Proxmox hosts with AMD CPUs (Ryzen & Epyc). The reader was able to reproduce the problem himself on some of the customer systems he supports.
The only solution is to change the virtual CPU to a generic model (e.g. "x86-64-ve") or an emulated Epyc CPU. Under Windows 11, this "only" affects the latest versions, i.e. 24H2. 23H2 or IoT LTSC versions are not affected by this.
Reader discussion in the German blog
German blog reader Meth0d had already posted this comment on the blog on June 11, 2025 and wrote that after the updates he got a BSOD with the message UNSUPPORTED PRCOCESSOR in his test VM, which runs under Proxmox on a host with an EPYC 9374F CPU.
German blog reader Bolko then got in touch in a follow up comment and referenced to various sources. On reddit.com there is the thread Cumulative Updates: June 10th 2025, which is about the June 2025 updates. There is this discussion that Windows machines with AMD processors will not receive the updates.
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Bolko asks what feature an AMD Ryzen is not supported to be able to do, so that Microsoft adds an extra query to the Windows update distribution? He writes that this even applies to AMD Ryzen 5000 Threadripper. He notes that there will be further updates in the next few days to address the AMD problem.
At German site heise there is the forum thread KVM/QEMU Ryzen den kb5060842, KB5058499 nicht installieren!, which refers to KVM/Qemu and concerns the same problem (thanks to Bolko for the link).
Proxmox forum: Discussion and workaround
German blog reader Christof had sent me a link in his e-mail to the thread AMD : BSOD unsupported processor since Windows build 26100.4202+ ( update kb5060842 + its preview kb5058499 ) in the Proxmox forum. The BSOD under Windows 11 is discussed there.
The workaround, as Christof wrote to me, and this is also confirmed elsewhere, is to change the virtual CPU to a generic model (e.g. "x86-64-ve") or an emulated Epyc CPU. This "only" affects the latest versions of Windows 11, i.e. 24H2. According to Christof, Windows 11 23H2 or IoT LTSC versions are not affected by this.
Similar articles:
Microsoft Security Update Summary (June 10, 2025)
Patchday: Windows 10/11 Updates (June 10, 2025)
Patchday: Windows Server-Updates (June 10, 2025)
Patchday: Microsoft Office Updates (June 10, 2025)
Windows 10/11: Preview Updates May 27, 28,2025
Windows 11 24H2: Out-of-Band Update KB5063060
Attention: June 2025 Patchday closes vulnerability CVE-2025-33073 in Windows
Windows network vulnerability CVE-2025-33073 (Reflective Kerberos Relay Attack)
Windows 10: June 2025 update KB5060533 causes Surface Hub v1 boot error
Caution: Windows June 2025 updates bricks Fujitsu computers
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