What does HRESULT 0x80090025 (NTE_FIXEDPARAMETER) mean?

NTE_FIXEDPARAMETER

NTE_FIXEDPARAMETER identifies a failure in provider-fixed key parameters. The selected CSP or key object exposes parameters chosen by the provider or hardware and does not permit the caller to replace them after creation. Diagnose provider-fixed key parameters at the first component that returned the value, not the last user-interface layer that displayed it; later cleanup and fallback attempts can produce different secondary errors.

What the code establishes

The provider has been reached, but the request does not satisfy the contract for selecting a container, setting a property, or passing an operation-specific structure. Treat names, scope flags, key specifications, structure sizes, nullability, and creation state as one transaction rather than debugging only the most visible argument.

Facts to preserve before changing state

• All flags and structure sizes at the returning API boundary
  Record the exact KP_* or provider parameter being set and whether the key has already been generated.
  Identifies the invalid selection or property boundary.
• Provider, container or key name, user-versus-machine scope, and create-versus-open intent
  Query the provider capabilities and supported key lengths, modes, or usages before choosing configuration values.
  Reveals scope and object-state differences hidden by a friendly UI.
• The same call captured from a successful request against the same provider
  Create a new key with supported creation-time properties instead of mutating a fixed property on an existing key.
  Prevents a successful fallback from being mistaken for a repair.

Build a timeline before changing state

• A known-good control result produced under the same identity, architecture, and provider selection.

Isolation procedure

Build a minimal call with explicit provider selection and a fresh nonproduction object. Add one flag or property at a time until the status returns in a provider-fixed key parameters investigation. This identifies whether the failure belongs to selection, object state, or one optional parameter without destroying the original keyset.

1. Use one known-good control that changes only the suspected part of the provider-fixed key parameters path.
2. Record where behavior first diverges in the provider-fixed key parameters path instead of judging only by the final application message.

Common wrong turns

NTE_NOT_SUPPORTED can cover an absent operation generally; this result is more specific because the parameter exists but is provider-controlled. Creating a new key under a different account can make the symptom disappear while changing provider, scope, ACL, and object identity simultaneously. That is a workaround, not a diagnosis of the original contract.

For provider-fixed key parameters, also retain the original numeric value; neighboring constants can encode materially different remediation paths even when an application presents all of them as an authentication, certificate, or security failure.

Proving the intended path works

The original object must be opened or configured with the documented parameter set under the intended scope, with no silent fallback to another provider or newly created container.

Technical references

These sources define the HRESULT and the relevant provider-fixed key parameters interface, protocol, or data format.

• Microsoft Open Specifications: HRESULT values.
• Microsoft: CryptAcquireContext.
• Microsoft: CNG Key Storage Providers.