5921 is a failover cluster result. Microsoft’s system-code table describes this value as: “An error occurred while reading from a stream of data. An unexpected number of bytes was returned.”
Code reference and safe checks
Read the exact screen and operation before selecting a repair. This page does not run commands or collect files, keys or logs.
What this value means
Microsoft’s system-code table describes this value as: “An error occurred while reading from a stream of data. An unexpected number of bytes was returned.”
ERROR_CLUSTER_PARTIAL_READ is a Win32 system result, usually returned to an application or API caller. It is not a Windows blue-screen code or a diagnosis of the whole PC.
| Code | 5921 |
|---|---|
| Hex form | 0x1721 |
| Symbol | ERROR_CLUSTER_PARTIAL_READ |
| Windows family | Win32 system codes |
| Source level | Microsoft code and symbol entry |
Safe next steps
- For 5921 (ERROR_CLUSTER_PARTIAL_READ), identify the cluster role, node, resource, and operation that returned this code. A desktop Windows repair sequence is not applicable.
- Review the cluster event and resource logs, then follow the exact Microsoft or vendor guidance for that role and version.
- Treat failover, quorum, storage, and production changes as administrator work with a rollback plan.
After one step, repeat the original operation and record whether this same code returns. A different code needs a fresh interpretation.
What this code cannot prove
The source establishes the identifier and reference meaning. It does not establish the cause on your specific PC.
Stop before changing security, licensing, directory or production settings on a managed device; involve the responsible administrator.
Official reference and verification
Source type: Microsoft code and symbol entry. Checked against the source set on Nov 2, 2026.
The reference gives the meaning of this identifier. It does not inspect your PC or guarantee that one repair will work.