Proxmox VE

A free, Debian-based platform for running virtual machines and containers on your own hardware.

Checked against the maker's own documentation on 21 September 2026.

Official site: www.proxmox.com · Documentation: read the manual · Release notes

What breaks between releases

The maker publishes these, in among the changelogs. They are the reason an upgrade that is routine on one machine locks you out of another.

• Proxmox VE 9.2

  Transient upgrade stall with a disarmed HA stack

  If you disarm HA for cluster-wide maintenance and then upgrade while HA resources are still migrating, the upgrade can stall on the pve-ha-manager package.

  Affects: Clusters that disarm HA during an upgrade on a version before 5.2.4; enterprise-repository users were never affected, and simply re-arming HA lets a stuck upgrade continue.

• Proxmox VE 9.2

  OVH-hosted systems can boot into memtest86+ instead of Proxmox

  9.2 adds a memtest86+ boot entry; on OVH servers managed by proxmox-boot-tool but not installed from OVH's own template, the boot process can pick memtest86+ instead of Proxmox VE.

  Affects: OVH customers using proxmox-boot-tool (ZFS/BTRFS root) who installed via IPMI rather than OVH's install template.

• Proxmox VE 9.2

  Windows VMs with Virtualization-based Security can freeze on Intel hosts

  Windows 11/2022/2025 guests using the host CPU type with VBS enabled can intermittently freeze, showing 100% CPU usage in the VM summary while frozen.

  Affects: Windows guests on Intel hosts using the host CPU type with VBS; fixed by upgrading qemu-server to 9.2.0 and moving affected VMs to machine version 11.0+pve2 or newer.

• Proxmox VE 9.1

  NVIDIA vGPU driver must be updated before upgrading

  Kernel 6.17 requires at least NVIDIA vGPU/GRID driver version 19.4; upgrading to 9.1 with an older driver breaks vGPU support.

  Affects: Anyone running NVIDIA GRID/vGPU; must update the driver first, or pin an older kernel after upgrading and unpin once the driver is updated.

• Proxmox VE 9.1

  Some Dell PowerEdge servers fail to boot kernel 6.17

  Certain Dell PowerEdge models report machine-check errors or fail to boot on kernel 6.17, while kernel 6.14 still boots successfully.

  Affects: Specific Dell PowerEdge hardware; workaround is enabling SR-IOV Global and I/OAT DMA in firmware, or pinning kernel 6.14.

• Proxmox VE 9.1

  LINSTOR/DRBD not yet compatible with kernel 6.17

  The DRBD kernel module fails to build via DKMS against kernel 6.17.

  Affects: Users running LINSTOR/DRBD storage; workaround is manually installing and pinning kernel 6.14 until a fix is available.

• Proxmox VE 9.1

  AMD Zen 5 RDSEED instruction bug on kernel 6.17.9+

  Affected systems disable the RDSEED32 CPU flag at boot, which then makes QEMU guests using CPU types that expose that bit (e.g. EPYC, EPYC-v4) fail to start unless the BIOS/microcode is updated.

  Affects: AMD Zen 5 systems on kernel 6.17.9 or newer without an updated amd64-microcode package or BIOS; can be mitigated by using an unaffected CPU type or, as a last resort, a kernel command-line flag.

• Proxmox VE 9.0

  Test repository renamed from pvetest to pve-test

  Systems still referencing the old 'pvetest' repository name in their sources list need to update it to 'pve-test'.

  Affects: Anyone using the no-subscription test repository.

• Proxmox VE 9.0

  Network interface names can change on upgrade

  Upgrading the kernel (e.g. from 6.8 to 6.14) can change NIC names; if the previous name isn't kept as an alternative name, network configuration and firewall rules referencing it stop working until manually fixed.

  Affects: Hosts upgrading from Proxmox VE 8.x to 9.0, especially with less common NIC hardware; the pve-network-interface-pinning tool can pin names to custom values before upgrading.

• Proxmox VE 9.0

  VirtIO virtual NIC default MTU behaviour changed

  A VirtIO vNIC with no MTU explicitly set now inherits the bridge's MTU instead of defaulting to 1500, which can silently change a guest's effective network MTU.

  Affects: VMs with VirtIO NICs left at the previous default MTU; the pve8to9 checklist script flags affected vNICs before upgrade.

• Proxmox VE 9.0

  AppArmor upgraded to version 4.1

  Some packages outside the core Proxmox VE distribution (for example the CUPS printing daemon) can regress under the newer AppArmor profiles, and there is a known issue with nested containers (Docker inside an LXC container).

  Affects: Hosts running AppArmor-confined services, or Docker-in-LXC setups.

• Proxmox VE 9.0

  VM.Monitor privilege removed

  The VM.Monitor privilege is dropped in favour of Sys.Audit plus more fine-grained guest-agent privileges, so custom roles built around VM.Monitor lose the access they used to grant.

  Affects: Admins with custom RBAC roles referencing VM.Monitor; the pve8to9 checklist script detects affected roles.

• Proxmox VE 8.4

  PXE boot on OVMF VMs now requires a VirtIO RNG device

  OVMF firmware now blocks PXE boot for guests without a random number generator, so PXE silently stops working until a VirtIO RNG device is added.

  Affects: Any VM using OVMF (UEFI) firmware together with PXE boot.

• Proxmox VE 8.4

  iGPU passthrough broken in legacy mode

  Passing an integrated GPU through to a VM fails when using legacy mode (legacy-igd=1) with the i440fx machine type.

  Affects: Users passing through an integrated GPU on i440fx; switching to the q35 machine type or non-legacy mode avoids the issue.

• Proxmox VE 8.4

  Newly created Ceph Squid OSDs crash

  OSDs created on Ceph 19.2.0 through 19.2.1-pve2 crash, particularly affecting erasure-coded pools.

  Affects: Ceph Squid clusters creating new OSDs; fixed in Ceph 19.2.1-pve3 or by manually changing the bluestore_elastic_shared_blobs setting.

• Proxmox VE 8.4

  "Download from URL" now uses the configured proxy for HTTPS too

  ISO/template/OVA downloads that previously bypassed the datacenter proxy for HTTPS connections now route through it, which can break downloads from internal HTTPS repositories the proxy cannot reach.

  Affects: Hosts with a datacenter proxy configured that download files via HTTPS directly from an internal-only repository.

• Proxmox VE 8.3

  IPAM backing-path change during cluster upgrade (technology preview)

  IPAM state changes made on nodes that are not yet upgraded during a rolling cluster upgrade are lost, because the IPAM database files move to a new location when the first node's libpve-network-perl package updates.

  Affects: Clusters using the technology-preview Proxmox VE IPAM with DHCP-enabled SDN VNets, only during the upgrade window itself.

• Proxmox VE 8.2

  Kernel 6.8 becomes the new default

  A major kernel version change can cause hardware-specific side effects.

  Affects: All hosts upgrading to 8.2, particularly those with less common hardware; can be avoided by pinning the proxmox-default-kernel package to version 1.0.1 before upgrading.

• Proxmox VE 8.2

  Network interface names can change

  NICs, especially models using the i40e driver, can be renamed (for example gaining an added port suffix) after the kernel upgrade, breaking existing network configuration.

  Affects: Hosts with i40e-based NICs; pinning interface names to MAC addresses beforehand avoids the problem.

• Proxmox VE 8.2

  DKMS kernel modules may fail to build

  Third-party kernel modules, such as the NVIDIA GRID 17.1 driver as of April 2024, fail to build against the new kernel 6.8.

  Affects: Hosts relying on DKMS-built drivers; workaround is pinning the proxmox-default-kernel package to the older version before upgrading.

• Proxmox VE 8.2

  Split lock detection can slow down VMs

  On host CPUs that support split lock detection, a VM performing misaligned memory accesses can be artificially throttled by the host kernel (kernel 5.19 or later).

  Affects: VMs performing misaligned memory access on affected CPUs.

• Proxmox VE 8.2

  intel_iommu now defaults to on

  Enabling IOMMU by default in the 6.8 kernel series can cause boot or stability problems on older hardware or systems with an outdated BIOS.

  Affects: Older Intel systems with buggy or out-of-date BIOS firmware; fixed by explicitly disabling intel_iommu on the kernel command line.

• Proxmox VE 8.1

  ZFS plus hugepages kernel bug on 6.5

  Starting a VM configured with hugepages on kernel 6.5 with ZFS can hit a kernel bug that requires rebooting the host.

  Affects: Hosts running ZFS together with VMs configured to use hugepages.

• Proxmox VE 8.1

  Some Intel Wi-Fi cards fail to initialize on kernel 6.5

  Cards such as the Intel AX201 can fail to initialize under the new kernel, which can cut off remote access if Wi-Fi is the server's only network connection.

  Affects: Hosts relying solely on an affected Intel Wi-Fi card for network access; avoid booting into the new kernel without physical access to the machine.

• Proxmox VE 8.1

  AMD fTPM hardware RNG disabled

  The hardware random-number generator is disabled on all AMD systems equipped with a firmware-based TPM, affecting anything reading from /dev/hwrng.

  Affects: AMD systems with an fTPM device; affected systems should switch their RNG source to an alternative such as /dev/urandom.

• Proxmox VE 8.1

  Dell BCM5720 NIC compatibility issue

  Certain 14th-generation Dell servers have compatibility problems with the tg3 driver under the kernel 6.5.11-based build.

  Affects: Specific Dell server models (T140, R240, R640 and similar); workaround is pinning the kernel to 6.2 or disabling X2APIC in the BIOS.

• Proxmox VE 8.1

  Default network configuration switches from ifupdown to ifupdown2

  Systems installed on top of Debian, or installed before Proxmox VE 7.0, switch to the ifupdown2 network implementation; IPv6 router-advertisement acceptance (accept_ra) now defaults to off instead of on when no gateway is configured, which can silently drop IPv6 auto-configuration.

  Affects: Upgraded (non-fresh-ISO) installs that relied on accepting router advertisements without a gateway configured; accept_ra 2 can be added back manually to the interface configuration.

• Proxmox VE 8.0

  Minimum supported browser versions raised

  The web UI now uses newer JavaScript, CSS and HTML features and requires Firefox 79+, Chrome/Chromium 85+, or Safari 14+; older browsers may show a broken or non-functional interface.

  Affects: Anyone accessing the web UI with an older browser version.

• Proxmox VE 8.0

  Storage content types must each use a separate directory

  Storage activation now fails on setups where different content types (for example ISO images and backups) were mapped to the same directory, or where content directories were manually symlinked to a common location.

  Affects: Storages with a custom content-dirs configuration that shares directories across content types.

• Proxmox VE 8.0

  Kernel 6.2 live-migration hang

  Incoming live migrations of a VM with a restricted CPU type (such as qemu64) from certain Intel-CPU source hosts still on kernel 5.15 or older can hang and pin one or more vCPUs at 100% usage.

  Affects: Migrations from older Proxmox VE 7.4 hosts onto 8.0 hosts, for VMs using a restricted guest CPU type; fixed in a later 6.2-based kernel build (pve-kernel-6.2.16-4-pve).

• Proxmox VE 8.0

  Degraded KSM performance on multi-socket NUMA hosts

  Kernel Samepage Merging (memory deduplication) performs worse on 6.2-based kernels on multi-socket NUMA systems, which can noticeably increase memory usage.

  Affects: Multi-socket NUMA hosts relying on KSM; the recommendation at the time was to stay on Proxmox VE 7 (with its 5.15-based kernel) until a fix landed.

• Proxmox VE 8.0

  QEMU 8.0 removes some deprecated features

  Guest configurations using the old '-chardev tty' or '-chardev parport' aliases, or automation calling the deprecated QMP commands get_link_status, snapshot-drive or delete-drive-snapshot, stop working.

  Affects: Setups with custom 'args' entries in guest configs, or scripts/automation that call the removed QMP commands.

See the full release history, newest first.