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Free Fix 0xC004D401

0xC004D401: Security Processor Reports a System File Mismatch

12 min read Updated October 4, 2026 Windows Activation & Licensing

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0xC004D401 is the security processor reporting a system file mismatch, and its symbolic name marks it as a tamper-detection result. Three things produce it: a third-party filter driver interfering with file access, genuinely damaged system files, and modified or malicious code on the machine. Repair first, then rule out the third.

Run these on the affected machine in an elevated Command Prompt, in order, then reboot

DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow
fltmc filters
  1. Run the repair pair first. DISM repairs the component store, which is the source sfc copies from, so running it first saves a wasted pass.
  2. Read the fltmc filters output and note anything that is not a Microsoft component. Antivirus, backup, encryption and virtual drive products all install filter drivers.
  3. Run a full malware scan with an up-to-date engine. This code is a tamper-detection result, and Microsoft’s guidance for it includes malware and incompatible DRM software among the causes.
  4. Start Windows in a clean boot with third-party services and startup items disabled, and try activation again. If it succeeds, re-enable software in groups until the failure returns.
  5. Uninstall the offending product through Settings rather than deleting its driver file, reboot, then retry slmgr /ato.

Do not delete a .sys file to get rid of a filter driver. Removing a file a service still expects can leave the machine unable to boot. Uninstall the product that owns it, or use the vendor’s own removal tool.

If that fixed it you can stop here. If not, the next section explains what the security processor is checking and why two of these codes are about versions rather than files.

Why it happens

Licensing does not trust the ordinary file system view of the world. A protected component – the security processor – verifies the binaries involved in licensing before they are used, so that a licence cannot be validated by code that has been swapped out. The check compares what it reads against what it expects and it fails closed. A mismatch produces a licensing error even though nothing about your licence has changed.

0xC004D401 is that check failing, reported as a system file mismatch. Its symbolic name in the platform is SL_REMAPPING_SP_PUB_TAMPER_MODULE_AUTHENTICATION – a tamper-detection result. That word matters. Microsoft’s guidance for this code lists malware and incompatible DRM software among its causes, alongside the more mundane ones. An article that tells you this is never about your licence and only ever about drivers will mislead the subset of readers whose machine was activated by a crack or hit by malware, and this one used to be that article.

0xC004D402 carries the same published text as 0xC004D401 – the security processor reported a system file mismatch – but its symbolic name is more specific: SL_REMAPPING_SP_PUB_TAMPER_SECURITY_PROCESSOR_PATCHED. The security processor binary itself was found modified. Treat it the same way as 0xC004D401 and check for tampering as well as for filter drivers.

Two of the remaining codes are about versions rather than files, and older versions of this article obscured that. 0xC004D10A is SL_REMAPPING_SP_STATUS_INVALID_SPAPI_VERSION: the security processor reported a version mismatch, meaning the security processor API version is not what the licensing service expects, which typically follows servicing or a feature update that only partly applied. 0xC004F00E is SL_E_MISMATCHED_SECURITY_PROCESSOR: the licence could not be used by the current version of the security processor component. Both point at servicing state, not at a driver.

0xC004D103 is deliberately generic: an error occurred, with no more specific cause encoded. There is nothing to decode, so read the Security-SPP entries in the Application log instead. 0xC004D101 has no published meaning at all.

A third-party filter driver is interfering

You have this one if fltmc filters lists drivers from products you installed, and activation succeeds in a clean boot but fails normally.

  1. Note every non-Microsoft entry from fltmc filters before you change anything.
  2. Update the suspect product to its current version first. Incompatibility with a newer Windows build is the usual story.
  3. If updating does not help, uninstall the product properly through Settings, then reboot.
  4. Retry activation with slmgr /ato, then reinstall the product and confirm the error does not return.

Virtual optical drive tools, disk encryption products and older backup agents install the low-level drivers most often implicated in this failure.

Malware or modified licensing binaries

You have this one if The machine was activated by a downloaded utility, or has a history you cannot account for, and repairs keep coming back to the same place.

  1. Run a full scan with an up-to-date engine before spending further time on drivers.
  2. Look for scheduled tasks and services you do not recognise, particularly ones running as SYSTEM.
  3. Repair with DISM and sfc /scannow, and if sfc cannot fix the same files after a successful DISM run, plan a clean installation.
  4. Where the installation was never genuinely licensed, put that right with a real licence once the machine is clean – repairs do not create an entitlement.

This is the cause the code is named after. It does not make it the most common one, but leaving it off the list is how readers with a compromised machine get sent to check their backup software instead.

System files are genuinely damaged

You have this one if sfc /scannow reports violations it repaired, or ones it could not repair, on a machine with no unusual software.

  1. Run DISM /Online /Cleanup-Image /ScanHealth to see the extent, then DISM /Online /Cleanup-Image /RestoreHealth to repair the component store.
  2. Run sfc /scannow afterwards and read the summary.
  3. Reboot and retry activation.
  4. If the same files fail repeatedly, check the disk and review the storage hardware before repairing again.

Servicing is half applied, and the versions no longer agree

You have this one if 0xC004D10A or 0xC004F00E, after a cumulative or feature update, often with Windows Update itself misbehaving.

  1. Let any pending update finish and reboot fully before diagnosing anything.
  2. Run the DISM and sfc sequence in that order.
  3. If updates remain stuck, resolve that first. A machine part way through servicing produces misleading licensing errors.
  4. Retry activation once servicing has settled.

These two codes are version mismatches rather than file mismatches: the security processor API version, or the security processor version the licence expects. Hunting drivers for them wastes an afternoon.

The licensing store is damaged as well

You have this one if System files check out clean, no unusual drivers are loaded, and licensing operations still fail.

  1. Reinstall the licence files: slmgr /rilc.
  2. Restart the licensing service: net stop sppsvc then net start sppsvc.
  3. Reboot and retry slmgr /ato.
  4. Read the Application log filtered on the Security-SPP source for the code behind the most recent attempt – which is exactly what 0xC004D103 is telling you to do.

Full reference

The six codes and what each actually points at

Code Reading Where to look
0xC004D401 The security processor reported a system file mismatch. A tamper-detection result Filter drivers, file corruption, malware, modified licensing binaries
0xC004D402 Same published text; specifically, the security processor component itself was found patched Tampering first, then filter drivers
0xC004F00E The licence could not be used by the current version of the security processor component Servicing state, not drivers
0xC004D10A The security processor reported a version mismatch – an invalid security processor API version Partly applied servicing or a feature update
0xC004D101 No published meaning. The symbolic name points at the security processor not having initialised Service state and system file health
0xC004D103 A generic security processor failure with no more specific cause encoded The Security-SPP entries in the Application log

Sorting one cause from another

Observation Where to look
Activation works in a clean boot A third-party service or driver
sfc /scannow repairs files and the error goes away System file corruption, now fixed
sfc repairs the same files on every run The component store is damaged. Run DISM first, and if it recurs, stop repairing
Failure began after installing security or backup software That product’s filter driver
Failure began after a feature update An older driver, or a version mismatch – check 0xC004D10A and 0xC004F00E
Nobody can account for how the machine was activated Tampering. Scan it, and read the licensing state honestly

Reading the log rather than guessing

0xC004D103 exists precisely because the security processor sometimes has nothing more specific to say. When you have it, the next step is not another repair command but the Application log filtered on the Security-SPP source, which records each licensing attempt and the value it carried. Microsoft’s own error text for any of these codes can be printed on the machine with slui.exe 0x2a followed by the code, which is the fastest way to confirm what your build reports rather than trusting a table.

Repair order, and why it is that order

  1. DISM /Online /Cleanup-Image /ScanHealth if you want to know the extent before you change anything.
  2. DISM /Online /Cleanup-Image /RestoreHealth to repair the component store.
  3. sfc /scannow, which repairs system files from the component store – so a healthy store first means fewer passes.
  4. Reboot, then retry activation.
  5. fltmc filters and a clean boot if the repair alone did not settle it.
  6. A full malware scan, which belongs in the list rather than at the end of it for a tamper-detection code.
  7. slmgr /rilc and a licensing service restart if system files are clean and licensing still fails.

Do not delete a driver file directly from the file system to get rid of a filter driver. Removing a .sys file that a service still expects can leave the machine unable to boot. Uninstall the product that owns it, and if the product will not uninstall cleanly, use its vendor’s removal tool.

When the answer is not a repair

Most machines producing 0xC004D401 have a driver problem or a servicing problem, and both are free to fix. But this is a tamper-detection code, and some machines producing it were never legitimately licensed – the licensing binaries were modified to make them appear activated, and the check is doing exactly what it was built to do. On those machines the repair sequence will complete and the state will come back, because nothing in it creates an entitlement. Where that is the situation, the honest end of the process is a clean installation and a genuine licence, not a longer list of commands.

Every code this article covers

Code What it points at Source
0xC004D401 The security processor reported a system file mismatch. A tamper-detection result: filter drivers, file corruption, malware and modified licensing binaries are all legitimate causes KB audit; not published on Microsoft Learn
0xC004D402 The same published text as 0xC004D401 – a system file mismatch – reported specifically because the security processor component itself was found patched or modified KB audit; not published on Microsoft Learn
0xC004F00E The licence could not be used by the current version of the security processor component: a version mismatch between the licence and the security processor KB audit; not published on Microsoft Learn
0xC004D10A The security processor reported a version mismatch – the security processor API version is not what the licensing service expects, typically after partly applied servicing KB audit; not published on Microsoft Learn
0xC004D101 No published meaning. The symbolic name points at the security processor not having initialised not published by the vendor
0xC004D103 A generic security processor failure: an error occurred, with no more specific cause encoded. Read the Security-SPP entries in the Application log KB audit; not published on Microsoft Learn

Confirm the fix worked

  1. sfc /scannow completes and reports no integrity violations.
  2. slmgr /ato completes without returning an error.
  3. slmgr /dlv reports a licence status of Licensed.
  4. A full malware scan with an up-to-date engine comes back clean.
  5. Reboot with all your normal software re-enabled and confirm activation still holds.

Questions people ask about this

Is this always a driver problem?

No, and treating it as one is how this error gets misdiagnosed. It is a tamper-detection result. Filter drivers and file corruption are common causes, but so are malware and modified licensing binaries, and the code is named after the last of those.

Do I have to uninstall my antivirus permanently?

No. Update it first, since incompatibility with a newer Windows build is the usual cause. If you do have to remove it to activate, reinstall it afterwards and confirm activation still holds; the licence does not need reapplying.

Why did this start after a Windows feature update?

Two possibilities, and the code tells you which. A driver that worked on the previous build can behave differently on the new one. But 0xC004D10A and 0xC004F00E are version mismatches – the security processor API version, or the version the licence expects – and those follow servicing that only partly applied.

What does 0xC004D103 tell me?

That an error occurred and nothing more specific was encoded. It is a generic failure by design. Read the Security-SPP entries in the Application log for the underlying cause rather than trying to interpret the value.

Is a clean install necessary?

Rarely, but not never. Reserve it for machines where sfc cannot repair the same files after a successful DISM run, which usually indicates deeper damage or failing storage – and for machines where the licensing state was manufactured rather than issued, because no repair creates an entitlement.

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