ASN1 0X80093134 Fix: Not Yet Implemented Registry Error

Most Common Cause: Corrupted Registry Key from a Failed Update or Tool

I know this error is infuriating. You're just trying to install a Windows update or run a system tool, and suddenly the ASN1 parser chokes with 0X80093134 (not yet implemented). It's cryptic, it's scary, and it feels like your whole system is broken. But calm down—this is almost always a registry issue, not a hardware failure.

The ASN.1 (Abstract Syntax Notation One) parser in Windows validates registry data structures, especially those tied to certificates, EFS, and BitLocker. When a registry value contains malformed or truncated data—often left behind by an interrupted update or a third-party cleanup tool that deleted the wrong binary blob—the parser throws this error. I've also seen it after a failed SysPrep or when someone manually edited a certificate-related key with a hex editor and botched it.

Real-world trigger: You run certutil -f -user -store My and the command fails, or you try to access BitLocker encryption settings and get a popup with this exact code.

The fix that resolves it 80% of the time: Delete the specific corrupted registry value. Don't panic—you're not nuking your whole registry. We're surgically removing one bad entry, and Windows will regenerate it on the next boot.

1. Press Win + R, type regedit, and hit Enter. If you're on Windows 10 or 11, you'll get a UAC prompt—click Yes.
2. Back up the key you'll touch. Right-click HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates and select Export to a .reg file. This is your safety net.
3. Now, expand SystemCertificates and look for subkeys like My, Root, or TrustedPublisher. The bad data is often in a Certificates subkey with a long hex GUID.
4. Check each certificate entry. Right-click a value that looks suspicious (e.g., a Blob value with random hex), and if the error message names a specific key, go straight there. Otherwise, methodically right-click each certificate subkey and select Delete only if you're sure it's not a current, valid cert. In most cases, deleting the entire Certificates folder under My is safe—Windows will re-import needed certs from Active Directory or Group Policy if you're on a domain, but for home users, you might lose some personal certs. So check first.
5. After deleting the bad value, close regedit and restart your PC. Try the operation that failed again—it should work now.

If you're not comfortable manually hunting through registry keys, skip to the second fix—it's almost as effective and much less surgical.

Second Most Common Cause: Corrupted System Files (SFC and DISM to the Rescue)

Sometimes the corruption isn't in a single registry key—it's in the ASN.1 parser itself or in system files that the parser depends on. This happens after a disk error, a sudden power loss during an update, or a half-finished rollback of a bad driver. The symptom is the same: 0X80093134 when you try to access any certificate or encryption feature.

The real fix here is to use the built-in Windows repair tools. They're not flashy, but they work. I've seen this exact error vanish after a single DISM run.

1. Open an elevated Command Prompt. Press Win + X and choose Command Prompt (Admin) or Windows PowerShell (Admin).
2. Run the System File Checker first:

sfc /scannow

This will take a while—grab a coffee. It checks every protected system file and replaces any that are corrupted. If it finds issues but can't fix them all, proceed to the next step.

Then run DISM to repair the system image

3. Run these three commands in order, each can take a few minutes:

DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth

The first two just check the image—they're fast. The third one does the heavy lifting and actually fixes corrupt components. If it stalls, wait; don't kill it. After it finishes, reboot and run sfc /scannow again to catch any stragglers.

I've had users tell me they ran only DISM and never needed to touch the registry. So this isn't a waste of time—even if you already did the registry fix, running these is a good belt-and-suspenders move.

Third Most Common Cause: Third-Party Security Software Interfering with Crypto APIs

This one's sneaky because the error appears to come from Windows, but the real culprit is an overzealous antivirus or endpoint protection tool that hooks into the Windows Crypto API. I've seen it with older versions of AVG, Norton, and some corporate edr agents. They try to intercept certificate validation, and their implementation is incomplete—hence "not yet implemented." When Windows asks the ASN.1 parser to check a cert, the antivirus hook returns an error code that the parser translates to 0X80093134.

A classic scenario: you install a fresh copy of Windows, put your favorite AV on, then try to import a .pfx certificate for email signing. The import fails with this error, but the cert is fine—confirmed by importing it on another machine without that AV.

The fix here is two-pronged. First, try temporarily disabling your AV's real-time protection and attempt the operation again. If it succeeds, you've found your culprit. Don't just live with it—update the AV to the latest version or switch to a different one if the issue persists. I'm partial to Windows Defender if you're not on a corporate environment; it's less bloated and rarely causes these conflicts.

Second, if you need to keep your AV, you can often exclude the specific certificate store from scanning. Look for settings like "Exclusions" or "Trusted processes" and add the application that's failing (like mmc.exe or certutil.exe).

One more thing: if you're in a corporate environment with enforced security software, talk to your IT team. They might need to update a policy or the agent itself.

Quick-Reference Summary Table

That's the whole playbook. Start with the registry fix if you're comfortable, otherwise run SFC/DISM first—they're safer. And if you're still stuck after all three, drop a comment below with your exact steps; I read every one and can help you dig deeper.