micjohnson777 · Nov 4, 2026 · Oct 28, 2026 · Oct 28, 2026 · Nov 4, 2026 · Nov 4, 2026
@@ -25,29 +25,15 @@ Containers start quickly, use fewer system resources than [virtual machines (VMs
 {{< /expand >}}
 
 {{< hint type=note >}}
-Containers created in TrueNAS 25.04 or 25.10, whether using the **Instances** screen (25.04.0 and 25.04.1) or the **Containers** screen (25.04.2 and later), migrate automatically during the upgrade to TrueNAS 26.
-
-Containers do not migrate automatically on TrueNAS Enterprise High Availability (HA) systems, or on Enterprise systems without the Apps license feature enabled.
-Contact [TrueNAS Enterprise Support](https://www.truenas.com/support/) if you have containers on one of these systems.
-
-A container also does not migrate if a container with the same name already exists in the new format, for example after a previous incomplete migration attempt, or if TrueNAS cannot resolve the source image of the container.
-Check the system log if a container does not appear after an upgrade.
-
-Legacy virtual machines displayed on the **Containers** screen in 25.10 are not migrated automatically.
-See [Migrating Instance VMs to Virtual Machines]({{< ref "/VirtualMachines/ManagingVMs.md#migrating-instance-vms-to-virtual-machines" >}}) for the manual procedure.
-{{< /hint >}}
-
-{{< hint type=note >}}
-Containers running in TrueNAS 25.10 migrate automatically during the upgrade to TrueNAS 26.
-
-Containers do not migrate automatically on TrueNAS Enterprise High Availability (HA) systems, or on Enterprise systems without the Apps license feature enabled.
-Contact [TrueNAS Enterprise Support](https://www.truenas.com/support/) if you have containers on one of these systems.
-
-A container also does not migrate if a container with the same name already exists in the new format, for example after a previous incomplete migration attempt, or if TrueNAS cannot resolve the source image of the container.
-Check the system log if a container does not appear after an upgrade.
+Due to backend technology changes in TrueNAS 27, containers on the **Containers** screen require migration.
+Containers created in TrueNAS 25.04 or 25.10, whether using the **Instances** screen (25.04.0 and 25.04.1) or the **Containers** screen (25.04.2 and later), migrate automatically during the upgrade to TrueNAS 27.
+Containers migrate automatically at the first boot after upgrading, except on HA-capable TrueNAS Enterprise systems.
+Contact [TrueNAS Enterprise Support](https://www.truenas.com/support/) if you have containers on a TrueNAS Enterprise system that does not migrate them.
 
 Legacy virtual machines displayed on the **Containers** screen in 25.10 are not migrated automatically.
 See [Migrating Legacy VMs to Virtual Machines]({{< ref "/VirtualMachines/ManagingVMs.md#migrating-legacy-vms-to-virtual-machines" >}}) for the manual procedure.
+
+See [Migrating Containers from TrueNAS 25.10](#migrating-containers-from-truenas-2510) for what TrueNAS migrates.
 {{< /hint >}}
 
 ## Setting Up the Containers Service
@@ -525,3 +511,39 @@ You can open a shell session directly from this card.
 {{< trueimage src="/images/SCALE/Virtualization/ContainersToolsWidget.png" alt="Tools Card" id="Tools Card" >}}
 
 Click **Shell** <span class="iconify" data-icon="mdi:console-line"></span> to open a **Container Shell** session for command-line interaction with the container.
+
+## Migrating Containers from TrueNAS 25.10
+
+During the upgrade to TrueNAS 27, TrueNAS automatically migrates containers created in TrueNAS 25.04 or 25.10.
+See the note at the top of this article for the systems that do not migrate automatically.
+
+The migration runs once, during the first boot after the upgrade to TrueNAS 27, and does not retry.
+Containers on a passphrase-encrypted pool do not migrate, because the pool is still locked at that point.
+
+The migration moves each container from <file>*pool*/.ix-virt/containers/*container_name*</file> to <file>*pool*/.truenas_containers/containers/*container_name*</file>, and moves the image each container uses to <file>*pool*/.truenas_containers/images</file>.
+TrueNAS does not delete anything. Data that is not migrated stays in <file>.ix-virt</file>.
+
+{{< expand "What TrueNAS Migrates" "v" >}}
+- Autostart and CPU binding settings.
+- The bridge and the default network settings.
+- File system devices. A 25.10 disk device becomes a file system device when its source is under <file>/mnt</file>.
+- NICs, which become VIRTIO NICs.
+- USB devices, matched by vendor and product ID.
+- GPUs, when the PCI address is still a valid GPU on the system.
+{{< /expand >}}
+
+{{< expand "What TrueNAS Does Not Migrate" "v" >}}
+- Legacy virtual machines. See [Migrating Legacy VMs to Virtual Machines]({{< ref "/VirtualMachines/ManagingVMs.md#migrating-legacy-vms-to-virtual-machines" >}}).
+- Proxy devices and other device types the containers feature does not support.
+- Containers cloned from another container.
+- Containers with an unreadable configuration.
+- Containers with a name that matches a container that already exists in the new format, for example after a previous incomplete migration attempt.
+- Containers when TrueNAS cannot resolve the source image.
+- Environment variables. To restore them, edit the container and add them again.
+- A privileged container keeps no privileged setting. It migrates with the **Default** ID mapping, which cannot be changed after the container is created.
+{{< /expand >}}
+
+After the upgrade, review the **Containers** screen and confirm each container migrated, and review the devices for each migrated container.
+If a container does not appear, open **Jobs** after the first boot and check the container migration job.
+The job shows unreadable configurations, unsupported devices, and name conflicts, but only until the next reboot.
+The system log can contain additional information.
@@ -335,8 +335,10 @@ To restore 2FA for an affected account after upgrading:
 #### Containers
 
 LXC containers, introduced as an experimental feature in earlier TrueNAS releases, are fully supported in TrueNAS 27.
-Containers running in TrueNAS 25.10 migrate automatically to TrueNAS 26, except on TrueNAS Enterprise High Availability (HA) systems and Enterprise systems without the Apps license feature enabled.
-Contact [TrueNAS Enterprise Support](https://www.truenas.com/support/) if you have containers on one of these systems.
+Due to backend technology changes in TrueNAS 27, containers on the **Containers** screen require migration.
+Containers migrate automatically at the first boot after upgrading, except on HA-capable TrueNAS Enterprise systems.
+Contact [TrueNAS Enterprise Support](https://www.truenas.com/support/) if you have containers on a TrueNAS Enterprise system that does not migrate them.
+See [Migrating Containers from TrueNAS 25.10]({{< ref "/Containers/ManagingContainers.md#migrating-containers-from-truenas-2510" >}}) for what TrueNAS migrates.
 
 TrueNAS 27 adds the following container improvements:
 
@@ -349,13 +351,13 @@ See [Containers]({{< ref "/Containers/ManagingContainers.md" >}}) for configurat
 
 #### Virtual Machines
 
-Legacy virtual machines from the **Instances** screen, still shown on the **Containers** screen in TrueNAS 25.10, are not automatically migrated to TrueNAS 26.
+Legacy virtual machines from the **Instances** screen, still shown on the **Containers** screen in TrueNAS 25.10, are not automatically migrated to TrueNAS 27.
 No migration tool, wizard, or notification exists for these VMs.
 TrueNAS does not preserve the VM configuration, UEFI variables, or Trusted Platform Module (TPM) state.
 The VM disk remains on the pool.
 
-Before upgrading, record each VM configuration and back up the VM disk while still running TrueNAS 25.10.
-See [Preparing to Upgrade to TrueNAS 26](https://www.truenas.com/docs/scale/25.10/scaletutorials/virtualmachines/#preparing-to-upgrade-to-truenas-26) in the TrueNAS 25.10 documentation.
+Before upgrading, while still running TrueNAS 25.10, record each VM configuration and zvol name, and take a recursive snapshot of the pool the instances use.
+See [Preparing to Upgrade to TrueNAS 27](https://www.truenas.com/docs/scale/25.10/scaletutorials/virtualmachines/#preparing-to-upgrade-to-truenas-27) in the TrueNAS 25.10 documentation.
 
 After upgrading, see [Migrating Legacy VMs to Virtual Machines]({{< ref "/VirtualMachines/ManagingVMs.md#migrating-legacy-vms-to-virtual-machines" >}}) to re-create the VM and reattach the VM disk.
 

@@ -440,7 +440,7 @@ See [Accessing NAS from VM]({{< ref "ContainerNASBridge" >}}) for more informati
 ## Migrating Legacy VMs to Virtual Machines
 
 Legacy VMs created using the **Instances** screen in 25.04.0 and 25.04.1 remained on the **Containers** screen through 25.10.
-TrueNAS 26 removes them from the **Containers** screen entirely.
+TrueNAS 27 removes them from the **Containers** screen entirely.
 No migration tool, wizard, or notification exists for them.
 Containers migrate automatically during the upgrade. These legacy VMs do not.
 
@@ -453,13 +453,13 @@ A guest operating system whose disk is unlocked by a TPM-bound key does not star
 
 {{< hint type=note >}}
 Complete the preparation steps before you upgrade, while the system still runs TrueNAS 25.10.
-None of the preparation steps are available after upgrading to TrueNAS 26.
-See [Preparing to Upgrade to TrueNAS 26](https://www.truenas.com/docs/scale/25.10/scaletutorials/virtualmachines/#preparing-to-upgrade-to-truenas-26) in the TrueNAS 25.10 documentation.
+None of the preparation steps are available after upgrading to TrueNAS 27.
+See [Preparing to Upgrade to TrueNAS 27](https://www.truenas.com/docs/scale/25.10/scaletutorials/virtualmachines/#preparing-to-upgrade-to-truenas-27) in the TrueNAS 25.10 documentation.
 {{< /hint >}}
 
 ### Migrating a Legacy VM Disk
 
-Complete this procedure after upgrading to TrueNAS 26, using the VM settings and zvol information you recorded while running TrueNAS 25.10.
+Complete this procedure after upgrading to TrueNAS 27, using the VM settings and zvol information you recorded while running TrueNAS 25.10.
 
 1. Go to **Datasets** and create or identify a standard dataset to hold the migrated disk, for example *tank/vms*.
 

@@ -12,19 +12,19 @@ Plan migrations immediately to avoid disruptions during upgrades.
 
 ### Legacy VMs
 
-{{< deprecation-status deprecated="25.04.2" removed="26" >}}
+{{< deprecation-status deprecated="25.04.2" removed="27" >}}
 
-Legacy virtual machines created using the **Instances** screen in 25.04.0 and 25.04.1, and still shown on the **Containers** screen through 25.10, are removed in TrueNAS 26.
+Legacy virtual machines created using the **Instances** screen in 25.04.0 and 25.04.1, and still shown on the **Containers** screen through 25.10, are removed in TrueNAS 27.
 No migration tool, wizard, or notification exists to move them automatically.
 Containers migrate automatically during the upgrade. These legacy VMs do not.
 
 Migration Path:
 
 1. While still running TrueNAS 25.10, record the configuration of each legacy VM and the location of the disk on the pool.
-2. Upgrade to TrueNAS 26.
+2. Upgrade to TrueNAS 27.
 3. Re-create the VM and reattach the disk using the migration procedure.
 
-Impact: A legacy VM does not appear anywhere in TrueNAS 26 after the upgrade. The VM disk remains on the pool, but you must re-create the VM configuration by hand and reattach the disk to it.
+Impact: A legacy VM does not appear anywhere in TrueNAS 27 after the upgrade. The VM disk remains on the pool, but you must re-create the VM configuration by hand and reattach the disk to it.
 
 See Also: