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Veeam Agent — Corrupt Install: Force Removal & Clean Redeploy (Error 1605)

Audience: T2 / T3 Version: 1.0 Last Updated: September 2026 Applies To: Veeam Agent for Microsoft Windows (v12 agents on current Windows 11 builds), Veeam Backup & Replication v12 → v13

Overview

This guide covers a corrupt Veeam Agent for Microsoft Windows install that can be neither repaired nor uninstalled, and the follow-on failure where the B&R server keeps a stale record of the removed agent and every rescan fails with Windows Installer error 1605.

Common symptoms:

  • Veeam Agent (v12) on the endpoint will not install, repair, or uninstall — installer rolls back or errors out
  • B&R rescan of the managed computer warns: Failed to connect to <host> — This action is only valid for products that are currently installed. Failed to invoke rpc command.
  • 1605 / ERROR_UNKNOWN_PRODUCT in Windows Installer logs on the endpoint
  • Seen after the v12 agent era on current Windows 11 builds; upgrading the B&R server to v13 does not clear it by itself

Root cause (two layers):

  1. Endpoint: the agent's MSI registration is corrupt, so Windows Installer can neither service nor remove the products. The only way out is manual de-registration (below).
  2. B&R server: after the endpoint is force-cleaned, the B&R configuration database still holds the old agent/managed-computer record. A passive rescan discovers but does not deploy — it tries to manage the package its database says is installed, the endpoint's Windows Installer answers 1605 (unknown product), and the rescan surfaces it as a connect/RPC failure. Another rescan will never fix this; the stale record has to go.

Part 1 — Force-remove the corrupt agent (endpoint)

⚠️ Back up the registry keys before deleting them. Export each key you touch to a dated folder (e.g. C:\Users\<user>\Desktop\veeam-reg-backup).

1.1 Delete services — order matters

Delete VeeamDeploySvc (Veeam Installer Service) FIRST. It self-heals and re-registers the other components; removing it last means it can put back what you just deleted.

# 1. Installer service first (self-heals if left for last)
sc.exe stop VeeamDeploySvc
sc.exe delete VeeamDeploySvc

# 2. Then the agent and transport services
Get-Service Veeam* | Select-Object Name, Status   # enumerate what's present
sc.exe stop  VeeamEndpointBackupSvc
sc.exe delete VeeamEndpointBackupSvc
sc.exe stop  VeeamTransportSvc
sc.exe delete VeeamTransportSvc

(Service names vary slightly by version — delete whatever Get-Service Veeam* returns, installer service first.)

1.2 De-register from Windows Installer — all three registration points

The corrupt install is registered in three places; all three must go or msiexec and the B&R deployer keep finding the ghost product.

Product GUIDs for the v12 agent generation this was written from (verify against the endpoint's own registry before deleting — GUIDs are version-specific):

Component Uninstall-key GUID Packed code (Installer\Products)
Veeam Agent for Windows {7796202E-3320-41ED-9A2C-14613AEED3D3} E20269770233DE14A9C24116A3EE3D3D
Veeam Backup Transport {A2D1052D-657D-48E3-8D7C-A77C8B07A665} D2501D2AD7563E84D8C77AC7B8706A56
VeeamDeployerService (registered as its own uninstall entry) —
  1. Uninstall keys — HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{GUID} (and the WOW6432Node equivalent) for the Agent, Transport, and VeeamDeployerService entries.
  2. Installer product registrations — HKLM\SOFTWARE\Classes\Installer\Products\<packed code> for both packed codes above.
  3. MSI UserData — HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Installer\UserData\S-1-5-18\Products\<packed code>\InstallProperties (delete the product node).

1.3 Scheduled tasks and reboot

  • Remove Veeam scheduled tasks: Get-ScheduledTask | Where-Object TaskName -like '*Veeam*' | Unregister-ScheduledTask -Confirm:$false
  • Reboot the endpoint. A half-present service that hasn't been fully released produces exactly the partial-connect + 1605 pattern on the next rescan.

1.4 Verify the endpoint is clean

Get-Service Veeam*                                              # nothing
Get-ScheduledTask | Where-Object TaskName -like '*Veeam*'       # nothing
Get-ChildItem 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall' |
  Get-ItemProperty | Where-Object DisplayName -like '*Veeam*'   # nothing

All three must return nothing before touching the B&R side.

Part 2 — Clear the stale record on the B&R server

Do not just rescan again. The rescan is what's failing; it queries the product the database still believes is installed.

  1. In the B&R console: Inventory → Physical Infrastructure → the protection group containing the endpoint.
  2. Right-click the computer → Remove from configuration (removes the stale agent/managed-computer record; existing backups stay in the repository and can be re-mapped).
  3. If the computer was added as an individually named member, re-add it; if the protection group discovers by AD/CSV, run Rescan on the group so it's rediscovered as a new computer.
  4. Right-click the rediscovered computer → Install agent (an explicit deploy — discovery alone does not necessarily push the agent).

If deployment still fails: rule out transport/RPC

Failed to connect … Failed to invoke rpc command can also be plain connectivity. From the B&R server against the endpoint:

Test-NetConnection <endpoint> -Port 135      # RPC endpoint mapper
Test-NetConnection <endpoint> -Port 445      # SMB (admin$ / C$)
Test-Path \\<endpoint>\admin$                # admin share with the B&R credential
Get-WmiObject Win32_OperatingSystem -ComputerName <endpoint>   # WMI/DCOM
Test-NetConnection <endpoint> -Port 6160     # Veeam Installer Service (once deployed)

Also confirm on the endpoint: Windows Firewall allows File and Printer Sharing, WMI, and Remote Service Management; and the credential B&R uses for it is a local administrator.

Verification

  1. Protection group rescan completes green — no 1605, no RPC warnings.
  2. Endpoint shows the current (v13-generation) agent version under the protection group.
  3. On the endpoint, Get-Service Veeam* shows the new agent services running.
  4. Run the backup job (or wait for its schedule) and confirm the first backup session succeeds — deployment green is not the finish line; a completed restore point is.

Quick Reference

Endpoint: delete VeeamDeploySvc first → delete agent/transport services → de-register all three registry points (Uninstall keys, Classes\Installer\Products, MSI UserData InstallProperties) → remove scheduled tasks → reboot → verify clean. B&R server: remove the computer from configuration → re-add/rediscover → explicit Install agent → verify green rescan + first successful backup. Rule of thumb: 1605 on rescan after a manual agent removal = stale B&R database record. Remove-and-re-add, don't re-rescan.

Document History

Version Date Author Changes
1.0 September 2026 Apis Initial creation from a live incident (corrupt v12 agent force-removed; v13 B&R rescan then failed 1605 against the stale managed-computer record). Related to the v13 fleet upgrade (HALO 1179664).

Confidential — Internal Use Only

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