Fixing STATUS_INVALID_PARAMETER_MIX (0xC0000030) – the real fix

You've hit 0xC0000030 – annoying, but fixable

This error pops up when Windows tries to load something – a driver, a service, or a system call – and the combination of parameters it receives makes no sense to the kernel. You'll see it as a blue screen or an app crash with STATUS_INVALID_PARAMETER_MIX. The good news: it's almost always a driver or registry issue, not hardware failure.

The fix that works 9 times out of 10

Skip the generic advice about running chkdsk or updating Windows. The real culprit is a driver that's passing a mismatched set of flags. Here's what to do:

1. Boot into Safe Mode with Networking – Press Shift + Restart from the login screen, then Troubleshoot > Advanced Options > Startup Settings > Restart > 5. You need networking to download drivers.
2. Open Device Manager – Right-click Start > Device Manager. Look for any device with a yellow triangle. That's a driver that's likely sending bad parameters. Common offenders: network adapters, USB controllers, and graphics cards.
3. Uninstall the suspect driver – Right-click the device > Uninstall device. Check the box that says "Delete the driver software for this device" if it appears. Don't skip this – the corrupted driver remains otherwise.
4. Reboot normally – Windows will reinstall a generic driver. If the error goes away, you found it. If not, repeat for the next suspect.

If you can't boot into Safe Mode at all (because the error happens during boot), use the Registry Editor from the Recovery Environment. Boot from a Windows installation USB, select Repair your computer > Troubleshoot > Command Prompt. Type regedit and load the hive from C:\Windows\System32\config\SYSTEM. Navigate to HKLM\SYSTEM\ControlSet001\Services and look for any service whose Start value is 0 (boot-start) and whose Type is 1 (kernel driver). Delete any that look suspicious – especially third-party antivirus or virtual adapter drivers.

# If you're in the recovery command prompt, this loads the hive:
reg load HKLM\OfflineSYSTEM C:\Windows\System32\config\SYSTEM

Why this fix works

What's actually happening here is that a driver is calling a kernel function like ZwCreateFile or IoCreateDevice with a set of flags that the kernel's internal validation logic rejects. The check is in ntstatus.h – the STATUS_INVALID_PARAMETER_MIX constant (0xC0000030) is returned when the parameter set is semantically invalid, not just out of range. A corrupted driver binary might have its flag values shifted by a memory error, or a registry entry might have a Parameters key with a DWORD that's set to an impossible combination.

The reason step 3 works is that uninstalling the driver removes those registry keys under HKLM\SYSTEM\CurrentControlSet\Services\<DriverName>\Parameters. When Windows reinstalls the driver fresh, it writes valid defaults. The driver's INF file specifies allowed parameter combinations, so the fresh install won't have the garbage data.

Less common variations you might see

Variation 1: The error appears in a specific app, not at boot

This usually means the app is passing bad parameters to a Windows API. Reinstall the app or update it. If you're a developer, check your CreateFile or DeviceIoControl calls – you're probably mixing FILE_FLAG_ and FILE_ATTRIBUTE_ flags that don't belong together. For example, FILE_FLAG_NO_BUFFERING requires sector-aligned buffers, and if you don't align them, you get this error.

Variation 2: The error appears when running chkdsk or formatting a drive

Here, chkdsk is sending a FSCTL with an invalid combination of parameters. This often means the filesystem driver (ntfs.sys or fastfat.sys) is corrupted. Run sfc /scannow from an elevated command prompt. If that doesn't fix it, run dism /online /cleanup-image /restorehealth. If still broken, you need a repair install of Windows.

Variation 3: The error appears in Event ID 7031 or 7034

This shows as a service crash. Open Event Viewer under Windows Logs > System. Look for the crash event – it'll say something like "The [service name] service terminated unexpectedly." The parameter mix error is logged as the exit code. To fix it, stop the service, delete its registry key under HKLM\SYSTEM\CurrentControlSet\Services\[ServiceName], then reinstall the software that owns the service.

Preventing this from coming back

The root cause is almost always a driver update gone wrong or a registry cleaner that deleted something it shouldn't. To avoid it:

• Never use registry cleaners – they strip out parameters that look unused but are defaults for a reason.
• Only install drivers from the manufacturer's site, not from Windows Update. Windows Update often pushes generic drivers that have different parameter expectations than the OEM's custom driver.
• Keep a system restore point before any driver update. If you get the error, roll back to the restore point and you're done in 2 minutes.
• If you're a developer, test your API calls with invalid parameter combinations during development. The kernel's validation is strict – a flag that's valid in one context might be invalid in another. The function RtlValidateUnicodeString is a common source of this error in kernel-mode code.

That's it. If none of this works, you're looking at a deeper corruption – run chkdsk /f /r on your system drive, then a repair install if that doesn't help. But for 90% of cases, the driver uninstall in Safe Mode is your fix.