Fix OSS_LIMITED 0X8009300A ASN Error on Windows

You're staring at that 0X8009300A error again, right? It's annoying, but it's actually a simple fix.

I've seen this one show up in all sorts of places — reading an encrypted email, applying a security update, or even just trying to open a signed PDF. The code "OSS_LIMITED" means the OS hit a limit while decoding ASN.1 data. The culprit is almost always a corrupted or oversized certificate store. Let's get this fixed.

The Quick Fix: Clear and Rebuild the Certificate Store

1. Open Command Prompt as Administrator. (Hit Windows key, type cmd, right-click, select "Run as administrator").
2. Run this command to reset the crypto store:

certutil -delstore -enterprise -user My

This deletes the personal certificate store for the current user. Don't panic — it doesn't touch any certificates installed by Group Policy or the machine store.

3. Now re-register the crypto DLLs:

regsvr32 /s softpub.dll
regsvr32 /s cryptdlg.dll
regsvr32 /s initpki.dll
regsvr32 /s mssip32.dll
regsvr32 /s wintrust.dll

4. Reboot your machine. Try whatever gave you the error again.

I had a client last month whose entire print queue died because of this — well, not the queue, but the secure print driver certificate was corrupted. This exact sequence fixed it in under 10 minutes.

Why This Works

The 0X8009300A error happens when Windows runs out of memory allocated for decoding ASN.1 structures inside certificates. ASN.1 is the language that certificates use to describe themselves — issuer, subject, serial number, extensions. When that data gets bloated (say, a certificate chain has too many intermediate CAs, or one cert has a badly formatted extension), the decoder hits its 64KB limit per structure and throws OSS_LIMITED.

Clearing the personal store removes any corrupted or oversized certificates you might have imported. Re-registering the DLLs makes sure the crypto subsystem isn't stuck with a bad version or stale pointers. The reboot forces the OS to rebuild its internal ASN.1 parser state from scratch.

Less Common Variations

Sometimes the error isn't in the user store but in the machine store. If the quick fix didn't work:

• For a machine-wide issue (like when Windows Update fails with this code), run:

certutil -delstore -enterprise -machine My

This clears the local machine's personal store. Be careful — it wipes out any locally installed certificates, like those from a VPN or RDP. You'll need to re-import them.

• If it's a specific file (like an .eml or .p7b file), the problem might be the file itself. I've seen PDF invoices with malformed signatures throw this. Try opening the file on a different machine. If it works there, the file is fine — your store is bad. If it fails there too, the file is corrupted. Ask the sender to re-export it.

• Third-party security software can also interfere. I once spent an hour chasing this error on a client's machine until I noticed their McAfee was hooking into crypt32.dll. Disable any third-party antivirus temporarily and see if the error goes away. If it does, update or replace the security software.

Prevention

This error usually comes back if you keep importing certificates that aren't clean. Here's how to avoid it:

• Always import certificates in .cer or .crt format — avoid .p7b if you can. The .p7b format wraps multiple certs into one ASN.1 structure, and that's where the limit hits hardest.
• Keep your intermediate CA store lean. Windows automatically trusts common CAs (like DigiCert, Let's Encrypt). You don't need to manually add every root or intermediate. I've seen admins import the entire chain and that's what causes the overflow.
• Run periodic certificate store checks. Use certutil -store My to list your personal certificates. If you see anything with a blank subject or issuer, delete it — it's corrupted data waiting to trip you up.
• Update Windows regularly. Microsoft has tweaked the ASN.1 parser over the years to handle larger structures. A machine on Windows 10 21H2 is more likely to hit this than one on 22H2 or Windows 11.

That's it. No registry hacks, no reinstalling the OS, no calling Microsoft support. A few commands and you're back to work. If you hit a variant I didn't cover, drop the specific file type or software in a comment — I've probably seen it.