Veeam: ‘Failed to open disk for read’

KB ID 0001577


EVERY VMware Job in Veeam Backup and Recovery failed with the following error, (for every Guest VM);

Processing SERVER-NAME Error: Failed to open VDDK disk [[DATASTORE-NAME] SERVER-NAME/SERVER-NAME.vmdk] ( is read-only mode – [true] ) Logon attempt with parameters [VC/ESX: [ESXi-SERVER-NAME.DOMAIN-NAME.COM];Port: 443;Login: [administrator@.vsphere.local];VMX Spec: [moref=vm-231];Snapshot mor: [snapshot-288575];Transports: [san];Read Only: [true]] failed because of the following errors: @Failed to open disk for read. Failed to upload disk. Agent failed to process method {DataTransfer.SyncDisk}.


The fact that I had upgraded the vCenter from 6.5 to 6.7 the same day is probably a clue! reconnecting and rescanning the vCenter did NOT resolve the problem.

Fix: Update Veeam Backup and Recovery, (In my case to 9.5 update 4b.)

  1. Stop and disable the Veeam Services.
  2. Reboot the server, (or go into task manager and kill and running Veeam processes)
  3. Mount the install ISO and carry out the upgrade.
  4. Reboot.

Problem solved!

Related Articles, References, Credits, or External Links

Veeam Backup and Recovery Download

Veeam Availability Suite Download

Veeam Backup For Office 365 Download

Veeam Backup For Azure Download

Veeam Backup for AWS Download

Author: PeteLong

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  1. Hi, I have to run replications of a VM (on a SAN) to a NFS datastore on a NAS. I use Veeam V7. After a few successful replication, I started to get errors like mentionnig “failed to open vddk disk” and “read-only mode” Could it be linked to the proxy transport mode configuration that’s been set to “Virtual Appliance” ? What would be the best choice for that kind of storage (NAS) ? Thanks !

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    • I’m confused, you can only replicate to a hyper visor? do you mean backup? And Veeam version 7 os VERY old you should update to 9.5 update 4.


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