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TPM_E_READ_ONLY
Technical interpretation
TPM_E_READ_ONLY (0x8028003E) belongs to TPM 1.2 nonvolatile-storage policy. The base What Is page already shows the short Windows message; the additional diagnostic value is that this result marks the TPM 1.2 NV index definition allows reads but not the attempted write.
The first producer to identify for this HRESULT is the TPM 1.2 NV permission and lifecycle checks. TPM 1.2 NV indices combine permissions, authorization mode, locality masks and lock semantics. Two indices of the same size can behave differently because those attributes were fixed when each index was defined.
The result value 0x8028003E should remain attached to the symbolic name. Some this result logs store the value as a negative signed integer; others expose only a generic CNG, WMI, BitLocker or enrollment message. Neither substitution identifies the TPM 1.2 NV index definition allows reads but not the attempted write as precisely as it.
Inputs and state to capture
- Producer for this HRESULT: the TPM 1.2 NV permission and lifecycle checks.
- Rejected invariant: the TPM 1.2 NV index definition allows reads but not the attempted write.
- Decisive capture: NV index, permission bits, define-space request that created it, requested offset and length, and any permanent or startup-clear locks.
- Safe comparison: query the public NV definition and write a disposable index created with explicit write permission.
Validate without broad changes
Build the result minimal case around the original command contract. Use a disposable object when the request can write NV data, advance a counter, change authorization state or consume a lock transition. The comparison is valid only when the caller, TPM generation and security policy remain the same.
| Question | Evidence for this HRESULT |
|---|---|
| What exact state was rejected? | the TPM 1.2 NV index definition allows reads but not the attempted write |
| Which layer owns the result? | The TPM 1.2 NV permission and lifecycle checks. |
| What must be correlated? | NV index, permission bits, define-space request that created it, requested offset and length, and any permanent or startup-clear locks |
| What is the controlled comparison? | query the public NV definition and write a disposable index created with explicit write permission |
Neighboring response codes
| Constant | Checkpoint represented by its standard message |
|---|---|
TPM_E_PER_NOWRITE | There is no protection on the write to the NV area — a separate checkpoint when compared with this result. |
TPM_E_BAD_LOCALITY | The locality is incorrect for the attempted operation — a separate checkpoint when compared with this result. |
TPM_E_FAMILYCOUNT | The family count value does not match — a separate checkpoint when compared with it. |
The codes above may appear in the same workflow, but they are not aliases. TPM_E_AREA_LOCKED is a mutable lock-state issue, while it follows from the index permission model.
Fix and verify
Do not attempt to mutate a read-only index; create a new index with the correct policy if the application owns the data model. Do not undefine a production NV index until its public attributes and authorization policy have been recorded. NV policy is established at definition time, and destructive recreation can remove counters, certificates or provisioning state.
Proof for this HRESULT consists of a successful replay plus validation of the intended key, PCR, NV, context, event-log, provider or service result. A software fallback or a newly provisioned blank TPM answers a different question than it.
Source material
- TCG: TPM 1.2 Main Specification — source for the checkpoint.
- TCG: TPM 1.2 Part 2 — NV structures and permissions — source for the checkpoint.
- TCG: TPM 1.2 Part 3 — NV commands — source for the checkpoint.
- Microsoft: Win32_Tpm class — source for the checkpoint.
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