Fix ERROR_SXS_IDENTITY_PARSE_ERROR (0x0000370D) on Windows

You'll see this error when launching an application — usually an older game, a custom-built tool, or something that installs its own side-by-side assemblies. The error message reads something like "The application has failed to start because its side-by-side configuration is incorrect" and the event log shows 0x0000370D. Trigger: you just installed a new program, updated Windows, or copied a portable app from another machine. The culprit here is almost always a corrupt or malformed manifest file inside the app's folder or in C:\Windows\WinSxS.

What's actually causing it

Side-by-side (SxS) assemblies are Windows' way of letting apps use specific DLL versions without stepping on each other. Every app that uses them ships an XML manifest that describes which versions it needs. ERROR_SXS_IDENTITY_PARSE_ERROR means the loader hit that manifest and couldn't make sense of it — something's wrong with the identity string, like a missing attribute or a broken character. Common causes: a partial download, a disk write error, or a botched registry entry.

Don't bother reinstalling Windows. The fix is usually targeted.

Step-by-step fix

1. Identify the offending manifest. Open Event Viewer (eventvwr.msc), go to Windows Logs > Application. Look for an error with source SideBySide. The detail will show the exact manifest path — something like C:\Program Files\CrazyOldApp\app.exe.manifest. Write it down.
2. Check the manifest syntax. Open that manifest file in Notepad or a proper XML editor. Look for the <assemblyIdentity> element. It must have name, version, processorArchitecture, and type attributes. If any attribute is missing, malformed, or contains illegal characters (like a trailing space or a pipe symbol), that's the problem. Fix it. Example of a valid entry:

   <assemblyIdentity name="MyApp" version="1.0.0.0" processorArchitecture="x86" type="win32" />

3. Delete and recreate the manifest. If the syntax looks fine but the error persists, delete the manifest file. Then reinstall the affected application — or copy a fresh manifest from the source if you have it. This forces Windows to regenerate the side-by-side cache.
4. Run SxS trace to isolate deeper issues. If the manifest is in WinSxS, don't touch it directly. Instead, enable SxS tracing:

   tracelog -start sxs -f C:\sxs.etl -guid #1eaa3bf4-4c6d-4f3f-bf4c-8b9b0a0a1b2c
       # Then reproduce the error, then stop with:
       tracelog -stop sxs

   Parse the ETL file with tracerpt C:\sxs.etl -o C:\sxs.xml and look for IDENTITY_PARSE_ERROR. It'll point you to the exact registry key or manifest that's broken.
5. Fix registry corruption. Sometimes the manifest file is fine but the registration in HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SideBySide\ is corrupted. Export that key as a backup, then delete the entry matching your app. Reinstall the app — it'll re-register cleanly.
6. Use System File Checker as a last resort. If the error comes from a Windows component (like Internet Explorer or a .NET framework assembly), run sfc /scannow from an admin command prompt. It'll replace any corrupted system manifests.

If it still fails

Check for disk errors. Run chkdsk /f C: and restart. A bad sector corrupting manifest files is rare but real — I've seen it twice in 14 years. Also verify the app is compatible with your Windows version. Some old apps ship manifests targeting Windows XP that choke on Windows 10/11. In that case, run the app in compatibility mode for Windows 7 — right-click the EXE, Properties > Compatibility tab. That bypasses the SxS check entirely for some cases.

One more thing: if you're dealing with a portable app that came from a USB stick, copy the entire folder to the local drive first. Running directly from removable media often triggers this error because the manifest can't be read fast enough or gets truncated during copy.

That's it. Nine times out of ten it's a manifest syntax issue or a registry glitch. You won't need to reinstall Windows.