STG_E_CSS_KEY_NOT_PRESENT: Fix the 0x80030307 Copy Protection Error

You have a disc your PC refuses to read, throwing 0x80030307 in your face. Annoying as hell.

Here's the quick fix, then I'll explain why it works.

The Fix: Disable the Copy Protection Filter

1. Press Win + R, type regedit, hit Enter. Say yes to the UAC prompt.
2. Navigate to:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e965-e325-11ce-bfc1-08002be10318}
3. You'll see numbered subkeys like 0000, 0001, 0002. Click each one and look for a string value called LowerFilters in the right pane.
4. If you find LowerFilters with the value secdrv.sys or PxHelp20.sys (or both), right-click it and delete it.
5. Close regedit and reboot.

After restarting, try the disc again. 9 times out of 10, the error is gone.

Why That Works

What's actually happening here is that Windows' CD/DVD driver stack has a filter driver that intercepts every read request to the drive. That filter — usually secdrv.sys (SafeDisc) or PxHelp20.sys (Protector) — checks if the disc carries a valid Content Scramble System (CSS) key. CSS is a low-level encryption scheme used on commercial DVD movies and some old games.

When the filter sees a sector without a valid CSS key — which happens on burned discs, scratched originals, or even legit discs with a damaged lead-in area — it returns STG_E_CSS_KEY_NOT_PRESENT (0x80030307). The drive itself is fine. The data on the sector is fine. But the filter panics and blocks the read outright.

The reason step 3 works: deleting that filter entry removes the filter from the driver stack entirely. The OS then talks directly to the IDE or SATA controller driver without the copy protection middleman. No CSS check, no error.

I've seen this on Windows 10 22H2 and Windows 11 23H2. It's not a hardware failure — it's an overprotective driver from 2003 that doesn't know the disc you're inserting is legitimate.

Less Common Variations of the Same Issue

1. The Filter is Missing But Error Persists

You check LowerFilters and it's empty or doesn't exist. But the error still shows. In that case, check UpperFilters next to it. Some optical drive utilities (like Nero or Alcohol 120%) install their own filters there. Delete UpperFilters too if it contains anything related to copy protection. Same reboot after.

2. Multiple DVD Drives — Single Filter

If you have both a DVD-RW and a Blu-ray drive, the filter is global — it applies to all drives in the same class GUID. Deleting it fixes all of them at once. You don't need to hunt per drive.

3. SafeDisc vs. Other DRM

SafeDisc (secdrv.sys) is the most common culprit. But PxHelp20.sys (Protector) and cdrom.sys variants also trigger this error. The fix is identical: delete the entire value string, even if it contains multiple .sys entries separated by spaces or newlines. The driver stack reads that string as a list; removing the whole list clears all filters.

4. After a Windows Feature Update

I've seen cases where a Windows 11 23H2 feature update re-enables the filter even after you deleted it. The registry key gets recreated by the update. If that happens, you need to set the filter's start value to 4 (disabled) instead of deleting it. Under the same class key, find the subkey for the filter driver: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\secdrv. Change Start from 1 (system) to 4 (disabled). Prevents Windows Update from re-adding the filter on the next upgrade.

Prevention: Keep That Filter Disabled

Once you delete LowerFilters and reboot, the filter stays gone — unless you install software that re-adds it. The worst offenders:

• Older versions of Nero Burning ROM (pre-2020)
• Alcohol 120% (uninstall it if you installed it recently)
• Daemon Tools (versions 4.x)
• Any SafeDisc-based game installer (they sometimes reinstall the filter on launch)

If you still need disc copy protection for old games, consider running them in a virtual machine (VMware or VirtualBox) with their own virtual optical drive. That keeps the filter off your host OS entirely.

One more thing: if you delete the filter and the error turns into a generic "Function incorrect" or drive not recognized, you might have accidentally deleted the cdrom.sys minidriver too. That's rare — just check the key again and make sure you only removed secdrv.sys or PxHelp20.sys, not everything. If you nuked the whole value, reboot, then run devmgmt.msc, right-click your DVD drive, uninstall device, then scan for hardware changes. Windows will rebuild clean filter entries.