STATUS_NO_LDT (0XC0000117) – Fix the LDT Size Change Error

1. Old 16-Bit or MS-DOS Application Triggering the Error

This is the most common cause. You're running a legacy program—something from the Windows 3.1 or MS-DOS era—that tries to resize its Local Descriptor Table (LDT). On modern 64-bit Windows (10, 11), 16-bit applications run inside NTVDM.exe, but the LDT is stripped out for security. The app crashes with 0xC0000117.

I saw this constantly when clients tried to run old accounting software or DOS-based games. The error pops right at launch, sometimes with a generic "The application was unable to start correctly" message.

Fix: Run in Compatibility Mode

1. Right-click the executable (e.g., oldapp.exe) and choose Properties.
2. Go to the Compatibility tab.
3. Check Run this program in compatibility mode for and pick Windows 95 or Windows 98/ME. Yes, that old.
4. Also check Reduced color mode and set to 8-bit (256) color—some DOS apps need it.
5. Click OK and try launching again.

If that doesn't work, open Command Prompt as Administrator and run:

cd /d "C:\Program Files (x86)\YourAppFolder"
regsvr32 /u ntvdm.dll
regsvr32 ntvdm.dll

This re-registers the NTVDM component. No luck? You'll need a 32-bit version of the app or a virtual machine (like Windows XP Mode). Skip the 64-bit compatibility troubleshooter—it never helps here.

2. Faulty or Outdated Driver Modifying the LDT

Less common but trickier: a kernel-mode driver (sound, video, or virtualization) is messing with the LDT. The error might show up when you plug in a device or launch a specific app. I've seen it with ancient Creative sound card drivers and some USB-to-serial adapters. The trigger is usually a driver that tries to allocate or resize the LDT—something NT kernel doesn't allow unless the process has one already.

Fix: Update or Roll Back the Suspect Driver

1. Press Win + R, type devmgmt.msc, press Enter.
2. Look for devices with a yellow exclamation mark, especially under Sound, video and game controllers or System devices.
3. Right-click the driver, select Update driver → Search automatically for updated driver software.
4. If that finds nothing, go to the manufacturer's site and download the latest driver manually. For example, if you have a Realtek HD Audio driver, get it from realtek.com, not Windows Update.
5. Still broken? Right-click the driver, choose Properties → Driver tab → Roll Back Driver. This reverts to a previous version that didn't cause the error.

Real-world scenario: I had a user with a Dell OptiPlex 9020. The error started after a Windows Update pushed a new NVIDIA audio driver. Rolling back the driver fixed it instantly. If rollback is grayed out, uninstall the driver completely, reboot, and let Windows reinstall the generic version.

3. Corrupt System Files or Missing LDT Support

This one's rarer but possible after a botched update or disk error. The LDT-related kernel structures get corrupted, and any process that touches them triggers 0xC0000117. You'll see it randomly, not just with one app.

Fix: Run System File Checker and DISM

1. Open Command Prompt as Administrator.
2. Run sfc /scannow. Let it finish—takes 10-15 minutes.
3. Then run DISM /Online /Cleanup-Image /RestoreHealth. This fixes the system image that SFC relies on.
4. Reboot after both complete.

If SFC finds corrupt files but can't repair them, the DISM step is critical. I've seen DISM fix this error on a Windows 11 22H2 machine where SFC was stuck. After the repair, the error never came back.

Still getting the error? Check disk integrity:

chkdsk C: /f /r

You'll need to schedule a reboot. Let it scan and fix bad sectors. That's your final option before a repair install.

Quick-Reference Summary Table

Start with the first cause—it's the most likely. If you're running a 64-bit system and still hitting this, double-check you're not using a 16-bit installer. They're notoriously broken on modern Windows. Good luck!