Fix ERROR_SXS_MANIFEST_FORMAT_ERROR (0X000036B4) Fast

What This Error Means (and Why You're Here)

I know this error is infuriating. You try to open an app — a game, some business software, or even a system tool — and instead get a popup saying the manifest file doesn't start with the right tag. The exact code is ERROR_SXS_MANIFEST_FORMAT_ERROR (0X000036B4). This tripped me up the first time too, back when I ran my help desk blog.

The short version: Windows uses XML-based manifest files to tell the system which side-by-side (SxS) assemblies an app needs. If that XML is malformed — missing the <?xml version="1.0" encoding="UTF-8" standalone="yes"?> declaration or the root <assembly> tag — the system throws 0X000036B4. It can happen after a bad update, a corrupted download, or someone editing the manifest with a plain text editor that stripped formatting.

Let's fix it. Start with the quickest fix. If it works, you're done. If not, move to the next.

Fix 1: The 30-Second Reinstall

More often than not, the manifest file itself is fine on disk but the app's installation is slightly corrupt. A quick reinstall replaces everything, including the manifest.

1. Right-click the Start button and choose "Apps and Features" (Windows 10/11).
2. Find the offending app in the list.
3. Click it and select "Uninstall". Follow the prompts.
4. Restart your PC — don't skip this. It clears cached SxS metadata.
5. Download a fresh copy of the installer from the official source (not a sketchy mirror). Reinstall.

If the error's gone, great. If not, the manifest on your system is genuinely broken. Move to the moderate fix.

Fix 2: The 5-Minute Manual Manifest Check

This assumes you know which app is failing. If you don't, check the Windows Application Event Log — look for Source: SideBySide, Event ID: 33 or 59. That log entry will tell you the exact path to the manifest file.

1. Open File Explorer and go to the app's installation folder (usually C:\Program Files\[AppName] or C:\Program Files (x86)\ [AppName]).
2. Look for files ending in .manifest. Common names: app.exe.manifest or [appname].manifest.
3. Right-click the manifest file, choose "Open with", and pick Notepad (or a better editor like Notepad++, but Notepad works).
4. The very first line must be the XML declaration. Like this:
   

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
   ... rest of the content ...
   </assembly>

   If the file starts with any other text — even a blank line, a space, or a comment — that's your problem.
5. If the declaration is missing, type it exactly as above on line 1. If the root <assembly> tag is missing or incomplete, add it. Save the file.
6. Try launching the app again.

Warning: If the file is binary or shows gibberish, it's not a text manifest — it's an embedded resource. Don't edit it; skip to the advanced fix instead.

Fix 3: The 15+ Minute Advanced Fix — SxS Store Rebuild

If the manifest file looks fine but the error persists, the system's side-by-side store itself is corrupt. This can happen after a failed Windows Update, a disk error, or malware. I've seen it with Windows 10 21H2 and 11 22H2 updates.

Step 1: Run the System File Checker

1. Open Command Prompt as Administrator (search "cmd", right-click, "Run as administrator").
2. Type sfc /scannow and press Enter. Let it finish — this takes 15-20 minutes.
3. If it reports corrupt files but can't fix them, run DISM /Online /Cleanup-Image /RestoreHealth. That's the Deployment Image Servicing and Management tool. It pulls clean system files from Windows Update.

Step 2: Re-register all SxS assemblies

1. In the same Administrator Command Prompt, run these two commands one at a time:
   

   regsvr32 /s atl.dll
   regsvr32 /s msvcp60.dll

   These aren't directly about manifests, but they re-register common runtime DLLs that the SxS system depends on.
2. Now run the SxS manifest rebuild tool:
   

   sfc /scanfile=c:\windows\winsxs\manifests\

   This scans all manifest files in the store. It's slow but thorough.

Step 3: Check for a corrupted .manifest file in WinSxS

Sometimes a single manifest in the component store is malformed. You can't edit those directly (they're protected), but you can replace them from a backup or the Windows image.

1. Go to C:\Windows\WinSxS\Manifests. This folder has thousands of files. Sorting by date modified might help find the culprit if you know when the error started.
2. If you have a system restore point from before the error, restore it. Otherwise, try an in-place upgrade (Windows 10/11 repair install) — that replaces all system files without removing your apps.

What NOT to Do

• Don't delete manifest files arbitrarily. Deleting a system manifest can break Windows components. Stick to the app-specific ones in Program Files.
• Don't use a generic "registry cleaner" — they won't fix SxS errors and often cause more problems.
• Don't ignore Event Viewer details. The specific manifest path and assembly name in the error log are your best clues.

When All Else Fails

If you've tried all three fixes and still get 0X000036B4 on a specific app, contact the app's vendor. Some older programs (pre-2010) shipped with malformed manifests that Windows 10 and 11 reject. The vendor might have a hotfix or a compatibility update.

One last thing: if the app is a game and you have an antivirus running, temporarily disable it and reinstall. I've seen Avast and McAfee corrupt game manifests during installation. That's rare, but real.