On-Prem CVAD | MCS catalog creation fails – existing connection was forcibly closed by the remote host

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Article ID: CTX696760

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Updated On:

Description

MCS machine catalog creation fails during the provisioning workflow, specifically in the “Copying Master Image” stage.

Observed Behavior

  • Catalog creation starts successfully
  • Upload process initiates (VDI upload)
  • Connection drops mid-transfer
  • Catalog creation fails

Error Observed

System.IO.IOException: Unable to write data to the transport connection
SocketException: An existing connection was forcibly closed by the remote host
StudioErrorId: ProvisioningTaskError
Error Source: CitrixOrchestration

Technical Context

  • Failure occurs during UploadDataToVdi process
  • Connection between DDC and XenServer is interrupted
  • Redirection to pool master leads to malformed request

Key Observation

Hosting connection was configured to a non-master XenServer node, causing:

  • Improper redirection
  • Malformed VDI upload URL
  • Transport-level failure during disk transf

Environment

This article is provided for informational purposes only. The described behavior is based on a specific environment and configuration. Ensure validation in a controlled environment before applying changes in production.

Cause

The issue occurred because the hosting connection was pointing to a non-master XenServer host.

During the MCS provisioning process:

  • Requests are redirected to the pool master
  • Incorrect configuration caused malformed VDI upload URL
  • This resulted in connection termination during data transfer

Resolution

Update the hosting connection to point to the correct XenServer Pool Master.

Steps

  1. Open Citrix Studio
  2. Navigate to Hosting → Connections
  3. Edit the hosting connection
  4. Update the hypervisor address to the Pool Master (FQDN/IP)
  5. Save configuration
  6. Retry catalog creation

Result

  • Catalog creation completes successfully
  • No further transport errors observed

Issue/Introduction

MCS machine catalog creation fails with error:

“Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host.”

This issue occurs during the master image copy phase due to an incorrect hosting connection configuration pointing to a non-master XenServer host.

Additional Information

Recommendations

  • Always configure hosting connection to Pool Master
  • Configure multiple hypervisor endpoints for HA
  • Ensure network stability (no MTU mismatch / timeout)
  • Validate sufficient memory on hypervisor
  • Restart DDC services if inconsistencies observed

Version Note

Upgrade to a supported CVAD version is recommended for stability improvements.

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