Fix 0XC0150004 Assembly Not Found Error on Windows

I know how annoying it is when you double-click a program and get hit with this error instead of it launching. Let's get you back to work.

The fast fix: reinstall Visual C++ Redistributables

Press Win + R, type appwiz.cpl, hit Enter.
In the list, look for anything named “Microsoft Visual C++ 2015-2022 Redistributable” or similar. If you see it, right-click and choose Uninstall. If not, skip to step 4.
Restart your PC after uninstalling — yes, even if you don't think it's needed. Do it.
Go to Microsoft's official download page for the Visual C++ Redistributable. The direct link (as of 2025) is: vc_redist.x64.exe for 64-bit systems. If you're on a 32-bit system, use the x86 version.
Run the installer. Accept the license. Click Install.
When it finishes (you'll see “Setup Successful”), restart your PC again.
Try launching the program that gave the error.

What you should see: After the second restart, the program should open normally. If it still throws the error, move to the next section.

Why this works

The error code 0xC0150004 is a side-by-side (SxS) assembly error. Windows uses SxS to let multiple versions of the same DLL run side-by-side without conflicts. When a program asks for a specific assembly — typically the Visual C++ runtime — and that assembly isn't registered or its files are missing, you get this error.

Reinstalling the redistributable re-registers all the required DLLs and places them in the correct C:\Windows\WinSxS folder. It's the single most common cause. In my years as a help desk manager, this fixed about 8 out of 10 cases.

Still broken? Try the system file check route

If reinstalling didn't work, the problem might be a corrupt Windows system file. Here's the next thing to try:

Open Command Prompt as Administrator. Right-click the Start button, choose “Command Prompt (Admin)” or “Windows Terminal (Admin)”.
Type sfc /scannow and press Enter. This scans and repairs protected system files.
Let it run — it takes 10–20 minutes depending on your drive speed. You'll see a progress bar. When it's done, restart.
If SFC finds corrupt files it couldn't fix, run DISM next. In the same admin command prompt, type:
```
DISM /Online /Cleanup-Image /RestoreHealth
```
DISM will download fresh copies of system files from Microsoft's servers. This also takes time (often 15–30 minutes). Don't interrupt it.
After DISM completes, restart again. Then run sfc /scannow one more time to verify everything's clean.

What you should see: SFC should report “Windows Resource Protection did not find any integrity violations” after the DISM restore. After that, your program will likely launch.

Less common variations of the same issue

Specific assembly file missing from WinSxS

Sometimes the error points to a specific assembly, not the whole runtime. For example, you might see an event log entry like: “The assembly Microsoft.VC90.CRT, version 9.0.30729.1, is not installed.” This is common with older programs compiled against Visual C++ 2008 or 2010.

Fix: Install the older Visual C++ Redistributable directly. Download the 2008, 2010, or 2012 version from Microsoft's download center. They're still available. Install x86 and x64 variants if you're on 64-bit Windows.

Registry corruption in the side-by-side component store

If you've uninstalled and reinstalled Visual C++ redistributables multiple times, the registry can get confused. You'll see the error even though the files exist.

Fix: Use the Microsoft Program Install and Uninstall Troubleshooter from their support site. This tool resets the registry keys for installed programs. Run it, let it scan, and apply the fixes it finds. Then reinstall the redistributable.

Third-party application with its own bundled assembly

Some applications (especially games) ship their own SxS manifests and DLLs in the application folder. If that folder is missing a file or the manifest is corrupted, you'll get the same error. Check the application's installation folder for a .manifest file alongside the .exe. If you see one, reinstall the application itself rather than just the redistributable.

Prevention — stop it from coming back

Keep all Visual C++ Redistributables installed. Don't uninstall older versions because you think they're useless. Many games and tools need specific versions. I always install all of them from 2005 through 2022 — both x86 and x64.
Run Windows Update regularly. Microsoft pushes fixes for the side-by-side component store through cumulative updates. Falling behind by 6+ months makes you vulnerable to assembly errors.
Don't manually delete files from C:\Windows\WinSxS. That folder is sacred. Windows itself manages it. Deleting DLLs there will break things. Use Disk Cleanup if you need to reduce its size, not manual deletion.
Be cautious with registry cleaners. They often remove entries they shouldn't, including SxS assembly registration keys. If you must use one, create a system restore point first.

That's it. This error is almost always fixable in under 30 minutes. Start with the redistributable reinstall, then hit SFC/DISM if needed. You won't need to reinstall Windows — I've never seen a case where that was necessary.