STATUS_SXS_ASSEMBLY_MISSING (0XC015000C): Quick Fixes

1. Reinstall the Visual C++ Redistributables (Most Common Fix)

I know this error is infuriating—you double-click an app, and bam, nothing happens except that error message. I've seen this dozens of times, and 9 times out of 10, it's because the app needs a specific Visual C++ runtime that's missing or broken. Windows relies on side-by-side (SxS) assemblies for these runtimes, and when one goes missing, you get 0XC015000C.

Here's the fix: download and install all the Visual C++ Redistributables from Microsoft's official site. You don't need to guess which one—just grab the latest Visual C++ Redistributable for Visual Studio 2015-2022 (x86 and x64). It's a single installer that covers versions from 2015 onward. But older apps might need the 2005, 2008, 2010, 2012, or 2013 runtimes too.

1. Go to this direct download link for x64 and this one for x86.
2. Run both installers as Administrator (right-click > Run as administrator).
3. Restart your computer.
4. Launch the app that was failing. Should work now.

If it still fails, search for the app's requirements. For example, older games like Fallout 3 on Windows 10 need the 2005 runtime specifically. You can get all-in-one packs from third-party sites, but I recommend sticking with Microsoft's official redistributable packages. They're reliable and virus-free.

2. Repair Corrupted System Files with SFC and DISM

If reinstalling runtimes didn't fix it, the problem might be deeper—a corrupted system file. Windows has a built-in tool called System File Checker (SFC) that checks and repairs these files. This tripped me up the first time too: I assumed reinstalling the app would fix everything, but the real culprit was a damaged system component.

1. Open Command Prompt as Administrator (search for cmd, right-click, Run as administrator).
2. Run: sfc /scannow. Let it finish—this takes 10-15 minutes.
3. If SFC finds errors but can't fix them, run DISM next: DISM /Online /Cleanup-Image /RestoreHealth
4. Restart your PC after DISM completes.

This combination fixes most file corruption issues. I've seen it resolve 0XC015000C on Windows 10 version 22H2 and Windows 11 version 23H2. The error often shows up after a failed Windows update or a bad app install, and SFC cleans it right up.

3. Reinstall the Application or Game in a Clean State

Sometimes the app itself is the problem. Maybe it installed partially, or the registry entries for its assemblies are broken. Don't bother with an in-place repair—uninstall it completely first. I'm opinionated here: most built-in repair options in Windows uninstallers are garbage and leave junk behind.

1. Go to Settings > Apps > Apps & features (Windows 11: Settings > Apps > Installed apps).
2. Find your app, click Uninstall, and confirm. If it offers a repair option, skip it—go straight to uninstall.
3. Delete any leftover folders in %ProgramFiles%, %ProgramFiles(x86)%, and %AppData% for that app.
4. Restart your PC to clear any locked files.
5. Redownload the installer from the official source and run it as Administrator.

This is critical for games and software that bundle their own runtimes—like Steam games or older Adobe products. They sometimes ship with a specific version of an assembly that conflicts with what's already on your system. A clean install lets the app register its assemblies fresh.

Quick-Reference Summary

Most users fix this with step 1. If you get stuck, the Windows Event Viewer under Applications and Services Logs > Microsoft > Windows > SideBySide often logs which specific assembly is missing—look for a dependentAssembly entry with a missing manifest or DLL name. That'll point you straight to the real fix.