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Backup task fails with "Failed to prepare guest for hot backup"


This KB  should only be applied if you observe all three corresponding error messages.

In the task summary following error message is displayed:
Failed to prepare guest for hot backup. Error: Cannot upload guest agent's files to the administrative share [\\...\ADMIN$]. Cannot copy file. Source file: [..\VeeamGuestAgent_X__.exe]. Target file: [\\...\ADMIN$\VeeamVssSupport\VeeamGuestAgent.exe]. CopyFile() failed. Win32 error:The process cannot access the file because it is being used by another process. Code: 32

Following lines can be observed in the job log (B&R6 and below) or task log (B&R7 and later):
Veeam Guest Agent is not started   at Veeam.Backup.Core.CViGuestInventoryInformer.IsEnabled()
   at Veeam.Backup.Core.CViGuestInventoryInformer.Veeam.Backup.Core.IGuestInventoryInformer.TryToInventory(CGuestInventoryInfo& inventoryInfo)
Cannot upload guest agent's files to the administrative share  [\\...\ADMIN$].
Cannot copy file. Source file: [..\VeeamGuestAgent_X__.exe]. Target file: [\\...\ADMIN$\VeeamVssSupport\VeeamGuestAgent.exe].

In the Guest VM VeeamVssSupport service hangs in starting or stopping state.
In VeeamVssSupport log (located in C:\ProgramData\Veeam\Backup) on the guest you can observe following:
            Updating Windows Firewall exceptions list.. Ok.
            Registering RPC protocol sequences used by the server.
            Registering RPC protocol sequences used by the server.. Failed.
ERR         Cannot register RPC protocol sequences used by the server.
ERR         Cannot force RPC run-time library to use all supported protocol sequences for receiving remote procedure calls.
ERR         RPC error:The parameter is incorrect.
ERR          Code: 87


Windows API function RpcServerUseProtseq(function registers RPC endpoint) fails.


This issue takes place, when RPC settings are not properly configured in registry.
Steps to fix the issue:
  1. Log on to Guest VM, press Start > Run > regedit
  3. Export this key to back it up first, then delete the whole Internet key (and it's sub-keys).
  4. Reboot your system and run Veeam job once again

Veeam Backup & Replication
5.x, 6.x, 7.x
Last Modified:
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