Fix NS_S_WMP_EXCEPTION (0X000D0FE9) UI Error in Visual Studio

You're coding along in Visual Studio 2022 (or 2019) and suddenly you get NS_S_WMP_EXCEPTION (0X000D0FE9)—an error about a UI component. It usually pops up when you're working with WPF or WinForms designers, or sometimes just opening a solution. The weird thing is the error code points to Windows Media Player, not Visual Studio directly. I've seen this happen after a Windows update, installing a third-party UI extension, or after a crash that left the VS cache in a bad state.

Don't panic. This isn't a hardware problem or a virus. It's almost always a corrupted cache or a DLL conflict between Visual Studio and Windows Media Player. Below are the three most common causes and their fixes, in order of likelihood and speed.

1. Visual Studio Cache Is Corrupted

This is the fix that works 80% of the time. Visual Studio keeps a local cache of component models, MEF (Managed Extensibility Framework) data, and designer metadata. When that gets borked, the WMP exception shows up because the UI components fail to load correctly.

1. Close Visual Studio completely. Make sure no instances are running—check your system tray for the VS icon.
2. Delete the cache folder. Open File Explorer and go to:
   %LOCALAPPDATA%\Microsoft\VisualStudio\
   You'll see folders like 17.0_xxxxxxxx (for VS 2022) or 16.0_xxxxxxxx (for VS 2019). The number changes based on your version. Inside each version folder, there's a ComponentModelCache folder. Delete that entire folder.
3. Reopen Visual Studio. It will rebuild the cache from scratch—this might take a minute or two. After it finishes loading, try opening the same project or designer that triggered the error.

Expected outcome: The error should be gone. If you still see it, move to the next fix.

2. Windows Media Player Configuration Is Off

Because the error code specifically references Windows Media Player (WMP), sometimes the problem is with WMP's component registration, not Visual Studio. This happens when a Windows update or a media codec pack (like K-Lite) messes with WMP's COM registration. Visual Studio uses WMP's UI components internally for some designer features.

1. Open Windows Features. Press Windows + R, type optionalfeatures, and hit Enter.
2. Find Media Features. Scroll down to Media Features. Expand it.
3. Uncheck Windows Media Player. Uncheck the box. Click OK. Windows will ask you to restart—go ahead and restart your PC.
4. After restart, re-enable it. Go back to optionalfeatures, re-check Windows Media Player, click OK, and restart again.
5. Re-register WMP DLLs (optional but thorough). Open Command Prompt as Administrator. Run these commands one at a time:
   

   regsvr32 wmp.dll
   regsvr32 wmpui.dll
   regsvr32 wmpdxm.dll

   Each should say "DllRegisterServer succeeded."
6. Open Visual Studio and test. The error should be gone.

I've had to do this on two machines after the Windows 11 22H2 update. It's a bit tedious, but it works when the cache fix alone doesn't.

3. Visual Studio Installation Is Damaged

If neither cache nor WMP fixes work, the VS installation itself might be corrupt. This usually happens if you installed extensions that modified the UI components or if a previous update failed. Don't uninstall yet—there's a repair option that's less painful.

1. Open Visual Studio Installer. Search for "Visual Studio Installer" in the Start menu and open it.
2. Find your VS version. Click the More button next to the version you're using (2022 or 2019).
3. Choose Repair. Select Repair from the menu. The installer will download and reinstall any missing or corrupted files. This takes 15-30 minutes depending on your internet speed.
4. After repair, reboot. Then open Visual Studio and see if the error is gone.

One more thing: If you recently installed a UI extension (like a theme or a designer tool), try disabling it first before doing the repair. Go to Extensions > Manage Extensions, disable suspect ones, and restart VS. Sometimes a bad extension triggers this exact error. The repair step is the nuclear option—use it only if the first two fixes fail.

Quick-Reference Summary Table

Start with the cache—it's fast and fixes most cases. If that doesn't cut it, the WMP reset is your next best bet. The repair is a last resort, but it's saved me a couple of times when nothing else worked.