0x800b0100 Missing Certificates: Fixing Servicing Stack Auth

If you’re seeing error 0x800B0100 during Windows Update or when installing a .msu/.cab package, you’re running into a code-signing and trust problem: Windows can’t verify the package signature, often due to missing or untrusted certificates in the servicing stack. This guide explains exactly what the error means, why it appears, and how to fix it with step-by-step procedures that go far beyond generic advice. You’ll learn how to repair certificate stores, reset Windows Update components, install the right Servicing Stack Updates, and verify signatures so your system can authenticate updates again.

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Understanding the Error

• What it is: Error 0x800B0100 is the Windows trust error TRUST_E_NOSIGNATURE, typically presented as “0x800B0100” or “No signature was present in the subject.” In practice, it means the Windows servicing stack (CBS/DISM/Windows Update) can’t build or validate a trusted certificate chain for the update’s catalog file (.cat) or the binary being installed.
• Where it appears:
  • Windows Update fails when checking, downloading, or installing updates
  • DISM /Add-Package or /RestoreHealth fails
  • In-place upgrade or .msu/.cab installs fail
• Why it’s critical: The servicing stack refuses to install anything it can’t authenticate. Until the trust chain is fixed, updates—including security fixes and Servicing Stack Updates—will continue to fail.

Common scenarios that trigger 0x800B0100

• Missing or outdated Microsoft root or intermediate certificates (e.g., after a fresh/legacy install, air-gapped systems, or blocked root auto-update)
• Time/date/TLS issues that prevent chain building or revocation checks
• Broken Windows Update components (SoftwareDistribution, Catroot2), or disabled services like Cryptographic Services
• Outdated Servicing Stack Update (SSU) or missing SHA-2 support (especially on Windows 7/Server 2008 R2)
• SSL/TLS interception by a proxy/firewall/AV that breaks signature validation or blocks certificate/CRL/OCSP retrieval
• Corrupted system files or malware tampering with catalogs, certificates, or trust settings

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Quick Reference Table

Cause | Symptom | Recommended Fix

• Missing Microsoft root certificates | Updates fail with 0x800B0100; CAPI2 errors 4107/11 | Re-enable root auto-update; import roots via certutil; ensure internet access to certificate endpoints
• Wrong date/time or TLS settings | Signature or revocation checks fail intermittently | Sync time; enable TLS 1.2; correct region/timezone
• Broken Catroot2 or SoftwareDistribution | Updates download repeatedly or never install | Reset Windows Update components; recreate Catroot2
• Cryptographic Services disabled | Verification failures in Event Viewer (CAPI2) | Enable/start Cryptographic Services (CryptSvc)
• Outdated SSU/SHA-2 support (legacy OS) | All updates fail on Win7/2008 R2 | Install SHA-2 (KB4474419) + SSU (KB4490628) manually
• Proxy/SSL inspection | Updates fail behind corporate network | Bypass SSL inspection for Microsoft update endpoints; fix proxy/WinHTTP settings
• Corrupted system files | SFC shows integrity violations | Run SFC and DISM with an ISO source or do an in-place repair
• Group Policy disabling root updates | Roots don’t refresh; CAPI2 shows trust errors | Enable Automatic Root Certificates Update in policy/registry

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Common Causes

• Missing/Outdated Certificate Chains

  • Automatic Root Certificates Update disabled via Group Policy
  • Air-gapped or restricted environments with no path to Microsoft’s root update service
  • Expired or untrusted intermediate certificates

• Incorrect System Time/Region or TLS Configuration

  • Date/time skew breaks certificate validity windows
  • TLS 1.2 disabled on legacy systems (breaking secure downloads and revocation checks)

• Broken Windows Update Components

  • Corrupted SoftwareDistribution or Catroot2 stores
  • Windows Update, BITS, or Cryptographic Services not running correctly

• Outdated Servicing Stack Update (SSU) or Missing SHA-2 Support

  • Particularly affects Windows 7/Server 2008 R2 if SHA-2 and SSU updates aren’t installed

• Network/Proxy/Firewall Interference

  • SSL inspection on update traffic
  • CRL/OCSP endpoints blocked
  • Misconfigured WinHTTP/WinINET proxy

• Corrupted System or Malware

  • Catalog (.cat) tampering or missing files
  • Code Integrity or CAPI2 logging trust failures

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Preliminary Checks

• Boot into Safe Mode (if updates repeatedly fail or you suspect interference)

  • Windows 10/11: Settings > Update & Security > Recovery > Advanced startup > Restart now > Troubleshoot > Advanced options > Startup Settings > Restart > press 4 for Safe Mode.
  • Alternatively, hold Shift while clicking Restart on the sign-in screen.

• Back up important data

  • Copy critical files to an external drive or cloud storage before making system-level changes.

• Run basic health checks

  • Elevated Command Prompt (Run as Administrator):

    chkdsk C: /scan

    sfc /scannow

    DISM /Online /Cleanup-Image /ScanHealth

  • If SFC reports it repaired files, run it again until it finishes clean. If DISM reports component store corruption, proceed to the step-by-step section to do an offline repair with an ISO.

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Step-by-Step Troubleshooting

Follow these in order. Test Windows Update after each major step.

1. Correct time, region, and time sync

• Set correct date/time/timezone in Settings > Time & Language.

• Force resync:

  w32tm /resync

  net stop w32time
  w32tm /unregister
  w32tm /register
  net start w32time
  w32tm /resync

• On domain-joined PCs, ensure your DC time source is accurate.

2. Verify essential services

• Open Services (services.msc) and ensure:
  • Windows Update (wuauserv) = Running
  • Background Intelligent Transfer Service (BITS) = Running
  • Cryptographic Services (CryptSvc) = Running
  • Windows Installer (msiserver) = Manual or Running during installs

3. Reset Windows Update components (including Catroot2)

• Elevated Command Prompt:

  net stop wuauserv
  net stop bits
  net stop cryptsvc
  net stop msiserver

  ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
  ren %systemroot%\System32\catroot2 catroot2.old

  net start cryptsvc
  net start bits
  net start wuauserv
  net start msiserver

• Reboot and try Windows Update again.

4. Reset proxy and networking for update endpoints

• If behind a proxy or VPN, temporarily disable and test on a clean connection.

• Reset WinHTTP proxy:

  netsh winhttp reset proxy

• Ensure the following are reachable or exempt from SSL inspection:

  • windowsupdate.microsoft.com
  • *.windowsupdate.com
  • *.update.microsoft.com
  • download.windowsupdate.com
  • *.delivery.mp.microsoft.com
  • *.microsoft.com
  • CRL/OCSP endpoints referenced by Microsoft certs

5. Re-enable automatic root certificate updates (policy/registry)

• Group Policy (gpedit.msc): Computer Configuration > Administrative Templates > System > Internet Communication Management > Internet Communication settings > “Turn off Automatic Root Certificates Update” = Disabled or Not Configured.

• Registry (elevated):

  reg query HKLM\Software\Policies\Microsoft\SystemCertificates\Root /v DisableRootAutoUpdate

  reg add HKLM\Software\Policies\Microsoft\SystemCertificates\Root /v DisableRootAutoUpdate /t REG_DWORD /d 0 /f

• Reboot after changing policy/registry.

6. Refresh Microsoft root certificates (online method)

• Elevated Command Prompt:

  cd /d %userprofile%\Desktop
  certutil -generateSSTFromWU roots.sst
  certutil -addstore -f root roots.sst
  certutil -addstore -f “TrustedPublisher” roots.sst

• This pulls current roots from Windows Update and adds them to the Local Machine stores. Try Windows Update again.

7. Install the latest Servicing Stack Update (SSU) and SHA-2 support

• Windows 10/11: SSUs are now bundled with LCUs, but you can manually install the latest cumulative update from the Microsoft Update Catalog. If updates won’t install, download the MSU that matches your build and try:

  wusa.exe “C:\Path\to\update.msu” /quiet /norestart

• Windows 7/Server 2008 R2 (legacy): Ensure these are installed in this order:

  • KB4490628 (SSU)

  • KB4474419 (SHA-2)

  • Then reattempt updates or install the latest monthly rollup. Use:

    wusa.exe “C:\Path\to\KB4490628.msu” /quiet /norestart
    wusa.exe “C:\Path\to\KB4474419.msu” /quiet /norestart

8. Repair system files and component store with a local ISO (DISM)

• Mount a Windows ISO that matches your installed edition/build. Assume it’s D:.

• Find the correct index:

  dism /Get-WimInfo /WimFile:D:\sources\install.wim

• Repair:

  DISM /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:IndexNumber /LimitAccess

• Run SFC again after DISM:

  sfc /scannow

9. Flush certificate caches and rebuild the chain

• Elevated Command Prompt:

  certutil -urlcache * delete
  certutil -setreg chain\ChainCacheResyncFiletime @now
  net stop cryptsvc
  net start cryptsvc

• Attempt the update again and check Event Viewer (see Advanced Diagnostics) for improved chain building.

10. Check for third-party security interference

• Temporarily disable or uninstall third-party antivirus/firewall/HTTPS-inspection tools. Ensure they’re not scanning or proxying Microsoft update traffic or blocking CRL/OCSP.
• If corporate proxy uses SSL inspection, create exceptions for Microsoft update and certificate endpoints.

11. Validate a failing package’s signature (optional but powerful)

• If you know the failing .cab/.msu or catalog, verify it:

  certutil -verify “C:\Path\to\package.cat”

• Or with signtool (from Windows SDK):

  signtool verify /kp /v “C:\Path\to\package.cat”

• Any trust chain errors here confirm the certificate/root issue.

12. In-place repair upgrade (last resort for persistent corruption)

• Use the Windows 10/11 ISO matching your build. Run setup.exe and choose “Keep personal files and apps.” This replaces system files and servicing components without wiping your data.
• After the repair, re-run Windows Update.

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Log and Crash Analysis Notes

About minidumps and this error:

• 0x800B0100 is a trust/authentication error, not a BSOD stop code. As such, minidump analysis (C:\Windows\Minidump) isn’t typically relevant. Instead, focus on servicing and trust logs:

Where to look instead:

• Windows Update logs

  • Windows 10/11: Generate a merged log:

    Get-WindowsUpdateLog

    (Run in PowerShell; it creates a Desktop log.)

• CBS/Servicing logs

  • C:\Windows\Logs\CBS\CBS.log
  • C:\Windows\Logs\DISM\dism.log

• CAPI2 (CryptoAPI) Operational log

  • Event Viewer > Applications and Services Logs > Microsoft > Windows > CAPI2 > Operational
  • Errors 4107/11 indicate trust chain or revocation issues tied to 0x800B0100.

• CodeIntegrity logs

  • Event Viewer > Applications and Services Logs > Microsoft > Windows > CodeIntegrity > Operational
  • May show signature validation failures during install.

Tip: If you must trace cryptographic chain-building, enable CAPI2 operational logging, retry the install, then review detailed chain-building paths and which cert/URL failed.

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Advanced Diagnostics

Use these when basic fixes don’t resolve the issue.

• Event Viewer deep dive

  • CAPI2 > Operational: Look for events 4107 and 11 around the time of failure. Expand the event XML to see which certificate, URL, or revocation check failed.
  • WindowsUpdateClient > Operational: Note failure codes, server contact issues, or authentication failures.
  • DISM and CBS logs: Search for 0x800B0100, TRUST_E_NOSIGNATURE, or “Failed to verify” lines.

• Signature and chain diagnostics

  • Verify a catalog:

    certutil -v -verify “C:\Path\to\package.cat”

  • Dump certificates:

    certutil -store -enterprise root
    certutil -store -user root
    certutil -store -enterprise “TrustedPublisher”

  • Force Windows to rebuild chain cache:

    certutil -setreg chain\ChainCacheResyncFiletime @now

• TLS/Schannel checks on legacy OS

  • Ensure TLS 1.2 is enabled (for legacy versions like Win7/2008 R2). Consult official Microsoft guidance for enabling TLS 1.2 via registry if needed. After changes, reboot.

• WSUS/Enterprise considerations

  • Verify WSUS supports SHA-2 (Server 2012 R2+ with required updates).
  • Ensure Group Policy “Specify intranet Microsoft update service location” is correct, and “Allow signed updates from an intranet Microsoft update service location” is enabled.
  • Exempt Microsoft endpoints from SSL inspection and allow CRL/OCSP egress.

Caution:

• Tools like Driver Verifier are not relevant for 0x800B0100 (they’re for driver stability/BSODs).
• Be careful editing registry and policy; document changes and create restore points.

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Post-Fix Checklist

• Run update again

  • Settings > Windows Update > Check for updates. Confirm successful installs with no new 0x800B0100 errors.

• Confirm logs are clean

  • Event Viewer: CAPI2 Operational shows no new 4107/11 events during update.
  • Get-WindowsUpdateLog shows normal scan/install flow.

• Re-run integrity checks

  • sfc /scannow
  • DISM /Online /Cleanup-Image /ScanHealth

• Verify services and startup

  • Ensure Windows Update, BITS, and Cryptographic Services are still running.

• Check time sync and network

  • Confirm time stays accurate and your network doesn’t block Microsoft endpoints or revocation checks.

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When to Seek Professional Help

• Enterprise/Domain restrictions

  • If Group Policy, SSL inspection, or WSUS configuration is causing signature failures and you can’t modify these settings, contact your IT administrator.

• Air-gapped or offline systems

  • You may need a controlled, offline method of importing trusted root and intermediate certificates. Ask IT/security for an organization-approved root bundle.

• Persistent trust or file corruption

  • If 0x800B0100 persists after in-place repair, a professional may need to evaluate disk health, malware, or deep servicing stack damage.

• Suspected malware/tampering

  • If Code Integrity or CAPI2 shows signs of tampered catalogs or unknown signers, run a full offline malware scan and consult professionals.

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Prevention Tips

• Keep time synchronized and TLS current

  • Use reliable time sources and keep secure protocol settings updated (especially on legacy OS).

• Don’t disable root auto-update

  • Leave Automatic Root Certificates Update enabled unless your organization centrally manages roots.

• Maintain the servicing stack

  • Install SSUs and LCUs regularly. On legacy systems, ensure SHA-2 support is in place.

• Avoid unnecessary “cleanup” of system stores

  • Don’t delete Catroot2/SoftwareDistribution routinely; only as part of a guided repair.

• Use reputable security software

  • Avoid SSL interception on Microsoft update traffic. Keep AV/firewall compatible with Windows Update.

• Back up and create restore points

  • Before major changes, take a system restore point or image.

• Monitor Event Viewer for early warnings

  • Periodically check CAPI2 and WindowsUpdateClient logs, especially after network/policy changes.

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Conclusion

Error 0x800B0100 means Windows can’t validate an update’s digital signature—a trust problem rooted in missing certificates, broken cryptographic services, or blocked validation paths. By correcting time/TLS, resetting update components, restoring Microsoft root certificates, ensuring the latest Servicing Stack Update and SHA-2 support, and verifying signature chains with certutil/signtool, you can reliably fix “0x800B0100: Missing Certificates” and restore servicing stack authentication. Most systems recover fully with the steps above, and you’ll be back to installing updates securely.

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FAQ

What does error 0x800B0100 mean in Windows Update?

It maps to TRUST_E_NOSIGNATURE—Windows couldn’t validate a package’s signature. The servicing stack won’t install updates it can’t authenticate, typically due to missing/untrusted root/intermediate certificates, broken Catroot2, or network/policy blocks affecting certificate validation.

Is 0x800B0100 a BSOD stop code?

No. It’s a Windows Update/servicing trust error, not a BSOD. Traditional minidump analysis isn’t applicable; focus on WindowsUpdate.log, CBS.log, DISM.log, and Event Viewer CAPI2 logs.

Can I safely delete Catroot2 and SoftwareDistribution?

You shouldn’t delete them arbitrarily, but renaming them as part of a controlled reset is a standard repair step:

• Stop update services
• Rename SoftwareDistribution and Catroot2
• Restart services
  Windows will rebuild them. Always try other steps first and back up important data.

How do I fix 0x800B0100 on Windows 7 or Server 2008 R2?

Install SHA-2 support and the latest SSU before anything else:

• KB4490628 (SSU)
• KB4474419 (SHA-2)
  Then attempt updates again. Ensure time is correct, Cryptographic Services are running, and root auto-update is enabled or roots are imported via certutil.

Can I fix “missing certificates” without internet access?

Yes, but you’ll need to import trusted roots/intermediates from a vetted source (e.g., an internal certificate bundle provided by IT/security). On an online machine, you can generate an .sst bundle with certutil -generateSSTFromWU and then import it on the offline system. Ensure you comply with your organization’s security policies.

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You’ve got this. Follow the steps in order, verify with the diagnostics, and you’ll restore servicing stack trust and get Windows Update running smoothly again. If you’re in a managed environment or offline, coordinate with IT to align certs, policies, and network rules for a lasting fix.