The sealed-node provisioner refuses to install onto a disk that still holds RAID or a foreign operating system, and it does not wipe the disk for you. Clear it yourself in the Hetzner rescue system before you register the server. Wiping is irreversible.

## What blocks an install

Syself Autopilot refuses to install onto the target disk in any of these cases. Each one can mean the server is still in use, or that the target is not the disk you think it is, so Syself Autopilot stops rather than risk wiping the wrong data.

| Blocker                 | What it means                                                                                                                         |
| ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| **RAID**                | A disk in the server carries a RAID member signature or an assembled RAID array. Sealed nodes run on plain disks only.                |
| **Ambiguous WWN**       | More than one disk reports the target's WWN (World Wide Name, a disk's unique hardware ID), so the target is not uniquely identified. |
| **LVM physical volume** | The disk the OS installs onto holds an LVM physical volume, part of the Linux Logical Volume Manager.                                 |
| **Foreign Linux**       | Another disk in the same server holds a Linux installation.                                                                           |

> [!WARNING]
> Wiping a disk destroys all data on it, permanently. Confirm you have the right server and that nothing on it needs keeping before you continue.

## Why Syself does not wipe for you

A wipe cannot be undone, and the platform never destroys data it did not create. A server you just bought can still carry a previous owner's array, and on a multi-disk server the disk you think is empty might be the one you meant to keep. Rather than guess, Syself Autopilot stops and asks you to clear the disk yourself. You do this once, when you first bring the server in, so a forgotten setting can never turn a data disk into a wiped one later. See [Order and prepare a Robot server](/docs/hetzner/apalla/servers-and-nodes/provision/order-and-prepare-a-robot-server) for where this fits when you bring a server online.

## Clear the disk in the rescue system

If the server is already a node, [remove it from the cluster](/docs/hetzner/apalla/servers-and-nodes/maintenance/remove-a-specific-node) first.

<Steps>
<Step>Boot into rescue</Step>

Open the [Hetzner Robot console](https://robot.hetzner.com/) and select the server.

<Steps>
<Step>Activate the rescue system</Step>

On the **Rescue** tab, choose your SSH key and keyboard layout, then activate it.

<Step>Reset the server</Step>

On the **Reset** tab, send a <Kbd keys="Ctrl+Alt+Del" /> reset.

</Steps>

The server reboots into rescue after a few minutes.

<Step>Wipe the disks</Step>

SSH into the server with the SSH key, then list the disks:

```console
$ lsblk
```

Disk names look like `nvme0n1` and `nvme1n1`, or `sda` for SATA devices. The machine object's status names the disk the install stopped on. Wipe that disk:

```console
$ wipefs -af /dev/nvmeXnX  # replace nvmeXnX with the disk name from lsblk
```

For a disk that is part of a software RAID array (managed by `mdadm`, Linux's software-RAID tool), stop the array first:

```console
$ mdadm --stop /dev/mdX
$ wipefs -af /dev/nvmeXnX
```

Repeat for every disk that needs clearing.

</Steps>

Once the disks are clean, register the server (or return it to your cluster configuration). Syself Autopilot claims the `HetznerBareMetalHost`, partitions the target disk itself, and starts provisioning. You do not need to partition or format anything by hand: clearing the blocking signature is enough.

## Related

- [Add bare-metal servers](/docs/hetzner/apalla/servers-and-nodes/provision/add-bare-metal-servers)
- [Serial console and rescue system](/docs/hetzner/apalla/servers-and-nodes/access/serial-console-and-rescue)
- [A server that will not provision](/docs/hetzner/apalla/servers-and-nodes/access/server-not-provisioning)