No issues to report so far.

No issues on the same test hosts i used for the last 2 batches of updates.

Installed on my usual test hosts. No issues so far.

Installed on my usual hosts, one of which has an E810 and used the ICE driver, no issues so far however i am not using LACP bonding on that host.

Installed on my usual batch of test hosts, no issues so far.

Installed on my usual batch of test hosts, so far so good.

@Andrew I have experienced this twice so far as well.

@stormi Updates deployed, no issues so far.

Updates deployed, no issues so far.

Installed on my usual test hosts without issues. However i am not using the qcow2 disk format anywhere yet

@florent I am using NBD for all backups yes but am not purging snapshots/usnig CBT.

Its so rare in fact that i haven't had it happen since since i made this post last week. (When i had it happen twice in 2 days). This is our production XOA it has occurred on so i wont be able to test a branch and i have never seen it happen on my sources install at home.

Installed on a handful of test machines. Not as many as usual as im being very cautious with this one for now. Everything rebooted and VMs started ok after. Using VHD for everything currently.

@pierrebrunet Thanks for the update. Glad to know its not something unique to our environment and you were able to track down the cause!

Since the XOA 6.3 release i have had a few random backup errors in an environment that has otherwise had fairly flawless backup performance for the last year. I cannot make out what exactly the error means but retrying the job allows it to succeed without issue. It is also very intermittent.

Log attached. 2026-04-07T01_00_03.075Z - backup NG.txt

If the issue persists i will submit a ticket to dive into it further but i have only had it happen 3 times since the release ofthe 6.3.x update so its hard to reproduce.

Replication target storage is a Pure C50R4 with NFS3 exports.

@florent I can confirm that this fixes the issue!

I created a brand new Windows 11 VM with a VTPM and Secure boot enabled and am able to reproduce this on a freshly created VM.

• Initial replication will work.
• Any follow up replications will fail with Error: VTPM_MAX_AMOUNT_REACHED(1)
• Retrying the job after the failure will succeed.

I tried removing the replica chain and let it start from scratch. The initial full replica was a success but unfortunately running a follow up incremental replication job results in the same error.

The entire transfer succeeds, it only seems to fail at the very end.

I have other VMs (Server 2022) with VTPMs that do not have this issue. The VM that is failing is Windows 11, and is the only Windows 11 VM we have running.

Looks like the issue still persists in 6.3.1?

Here is since installing the latest update yesterday:

Since updating to XOA 6.1.3 i have a VM that has secure boot enabled and will fail to replicate with the error:

"VTPM_MAX_AMOUNT_REACHED(1)"

Retrying the backup allows it to complete.

"data": {
            "id": "69d826f4-383c-f163-b59a-8f3ea5132fd1",
            "isFull": false,
            "name_label": "C50-DR-Win-NFS3-SR1",
            "type": "SR"
          },
          "id": "1775101037617",
          "message": "export",
          "start": 1775101037617,
          "status": "failure",
          "tasks": [
            {
              "id": "1775101039730",
              "message": "transfer",
              "start": 1775101039730,
              "status": "failure",
              "end": 1775101063330,
              "result": {
                "code": "VTPM_MAX_AMOUNT_REACHED",
                "params": [
                  "1"
                ],
                "call": {
                  "duration": 3,
                  "method": "VTPM.create",
                  "params": [
                    "* session id *",
                    "OpaqueRef:5263e3da-0772-f8c5-5344-32e81c08c37a",
                    false
                  ]
                },
                "message": "VTPM_MAX_AMOUNT_REACHED(1)",
                "name": "XapiError",
                "stack": "XapiError: VTPM_MAX_AMOUNT_REACHED(1)\n    at XapiError.wrap (file:///usr/local/lib/node_modules/xo-server/node_modules/xen-api/_XapiError.mjs:16:12)\n    at file:///usr/local/lib/node_modules/xo-server/node_modules/xen-api/transports/json-rpc.mjs:38:21\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)"
              }
            }
          ],
          "end": 1775101063749
        }

It appears to be trying to create a new TPM on the replica when one already exists?

Not sure why it fails during the job run but completes during a retry but it is consistent in its behaviour.

Happy to report from my limited testing that as of this morning this appears to be fixed in master.