Fix NS_E_DVD_INVALID_DISC_REGION (0XC00D1165) in Windows

Your DVD player's region code doesn't match the disc's region. Quick fix: change the DVD drive's region in Windows—but you only get 5 changes total.

Quick answer: Open Device Manager, find your DVD drive under DVD/CD-ROM drives, right-click, select Properties > DVD Region, choose your region, and click OK. You only get 5 region changes total—use them wisely.

Why this error happens

DVDs are region-locked by design. The world is split into six regions (Region 1 = US/Canada, Region 2 = Europe/Japan, etc.), and your DVD drive has a stored region code that Windows reads when you pop in a disc. If the disc's region doesn't match the drive's saved region, you get the NS_E_DVD_INVALID_DISC_REGION (0XC00D1165) error. Windows Media Player or any Windows-based DVD player will refuse to play it.

I've seen this most often when someone buys a DVD from a different country (like a UK Region 2 disc played on a US Region 1 drive) or when a drive's region is accidentally set to a wrong value by a previous movie. The drive remembers the last region you set, and you can only change it five times before it locks permanently to the last region you chose.

Fix step-by-step

Open Device Manager. Press Win + X and select Device Manager. Or type devmgmt.msc in the Run dialog (Win + R).
Find your DVD drive. Expand the DVD/CD-ROM drives section. You'll see something like "HL-DT-ST BD-RE BH16NS40" or "TSSTcorp DVD+-RW SU-208GB".
Open properties. Right-click the drive and choose Properties.
Go to the DVD Region tab. Click it. You'll see a map with regions and a dropdown or radio buttons for region selection.
Select the correct region. Pick the region that matches your disc. For a US disc, that's Region 1. For a UK disc, Region 2. Check the DVD's packaging—it usually has a region symbol (a globe with a number).
Click OK. Windows will ask you to confirm. The change takes effect immediately. You don't need to restart.
Try playing the disc again. Open Windows Media Player or your preferred DVD app. The error should be gone.

What if that doesn't work?

Sometimes the DVD Region tab is missing. That usually means your drive is set to a default region (often Region 1 for US drives) and Windows doesn't show the tab because the drive's firmware doesn't support region changes through Windows. Or the drive is region-free (RPC-1) and doesn't bother with region checks.

If the tab is missing or grayed out:

Update the DVD drive's firmware. Check your drive manufacturer's website for a firmware update. I've seen older LG and Samsung drives hide the region tab until you flash a newer firmware. Be careful—flashing wrong firmware can brick the drive.
Use VLC media player. VLC ignores the region check entirely for most discs. Download VLC from videolan.org, install it, open it, go to Media > Open Disc, select your DVD drive, and play. VLC bypasses the Windows DVD decoder that triggers the error. This is the easiest workaround.
Check for RPC-2 vs RPC-1. Some drives are RPC-2 (region-locked by firmware) and hide the region tab in Windows. You can check your drive's status with free tools like DriveRegion or DVD Region+CSS Free. If it's RPC-2, you're stuck—you can only change region via the drive's own utility (if available) or flash it to RPC-1 with hacked firmware (not recommended unless you know what you're doing).

Alternative fix: Change region via the registry (advanced)

I don't usually recommend this because it's flaky and can mess up other settings, but if you're out of region changes and the drive is RPC-2, you can try editing the registry to reset the counter. This doesn't always work on modern Windows 10/11 builds—Microsoft locked it down.

Open Regedit (Win + R, type regedit)
Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}
Look for subkeys with numbers (0000, 0001, etc.) until you find one with a DriverDesc matching your DVD drive.
Inside that subkey, find the DWORD named "RegionCount" or "RegionCode".
Delete it or set it to 0. Reboot.

I've seen this work on Windows 7 but rarely on Windows 10 version 20H2 or later. Your mileage may vary. Back up the registry first.

Prevention tip

Only change your DVD drive's region when you absolutely need to. Each change uses one of five slots. If you hit zero, the drive locks to the last region permanently, and you'll need a new drive to play discs from other regions. If you frequently watch DVDs from different countries, get a region-free DVD player (software or hardware) instead of changing the drive's region repeatedly. VLC is your friend—use it for all DVD playback and avoid Windows' region check entirely.

I tripped over this error myself when a friend brought back a Region 2 Japanese anime box set. My drive was set to Region 1. One change later, it worked fine. But I made sure that was the only change I'd ever need—because once you're out of changes, you're out.