Fix 0x0000370C: Duplicate attribute in SXS identity

This error means a side-by-side assembly manifest has two entries for the same attribute. The fix is to repair or rebuild the corrupted manifest file.

Quick answer

Run sfc /scannow from an elevated Command Prompt, then DISM /Online /Cleanup-Image /RestoreHealth. If that doesn't work, find the corrupted manifest file in %windir%\WinSxS and replace it from a known-good backup or another machine.

What this error actually means

Windows uses side-by-side (SxS) assemblies to keep different versions of DLLs and other components from stepping on each other. Each assembly has a manifest—an XML file that says what version it is, what dependencies it needs, etc. The error 0x0000370C (ERROR_SXS_IDENTITY_DUPLICATE_ATTRIBUTE) pops up when that manifest contains two definitions for the same attribute, like two <assemblyIdentity> entries with the same name but different values. The side-by-side loader can't pick which one to trust, so it bails out.

This usually happens after a botched Windows update, a third-party installer that mangled a system file, or a manual edit gone wrong. You'll see it when trying to launch certain apps—maybe a game, maybe a business tool—right after a reboot. The event log might point to a specific assembly like Microsoft.Windows.Common-Controls or something from a vendor.

Fix steps

Step 1: Check the exact assembly and manifest

Before throwing tools at it, find out which file is causing the trouble. Open Event Viewer (eventvwr.msc), go to Windows Logs > Application, and look for warnings or errors with source SideBySide. The event details will show the assembly name and path. Write it down—you'll need it if the standard repair doesn't cut it.

Step 2: Run System File Checker

Open Command Prompt as Administrator (right-click Start, choose Command Prompt (Admin) or Windows PowerShell (Admin)). Run:

sfc /scannow

This scans all protected system files, including SxS manifests, and replaces corrupt ones from the local cache. Let it finish—it can take 10-20 minutes. If it finds issues but can't fix them all, move to step 3.

Step 3: Use DISM to repair the system image

DISM can pull fresh copies of corrupted files from Windows Update. Still in the admin prompt, run:

DISM /Online /Cleanup-Image /RestoreHealth

This connects to Microsoft's servers to get clean versions. If you're offline, you can point it to a mounted ISO or a network share with the same Windows version. Example:

DISM /Online /Cleanup-Image /RestoreHealth /Source:C:\mount\windows /LimitAccess

After DISM finishes, run sfc /scannow again. The combination usually fixes most SxS corruption.

Step 4: Reboot and test

Restart your machine. Try launching the app that showed the error. If it works, you're done. If not, the manifest file itself is likely irreparably damaged.

Alternative fixes if the main one fails

Manually replace the manifest

If you know the exact manifest path from the event log, you can replace it. First, get a clean copy from another machine with the same Windows version and update level. For example, if the file is C:\Windows\WinSxS\Manifests\x86_microsoft.windows.common-controls_6595b64144ccf1df_6.0.19041.1_none_...manifest, copy that file from a healthy PC to a USB stick. Then boot your broken machine into Safe Mode with Command Prompt (hold Shift while clicking Restart, then Troubleshoot > Advanced Options > Startup Settings > Restart). Use copy or xcopy to overwrite the bad manifest.

Be careful: replacing system files manually can break things if you pick the wrong version. Only do this if you're sure about the source.

System Restore

If the error started after a recent change, roll back with System Restore. Type rstrui in the Start menu, pick a restore point from before the problem began. This reverts system files, including SxS manifests, to that state.

Use the Windows Update Troubleshooter

Go to Settings > Update & Security > Troubleshoot > Additional Troubleshooters > Windows Update. Run it. It resets some SxS-related components and can clear up manifest issues caused by update failures.

Prevention tip

Stop third-party cleanup tools—CCleaner, Registry Booster, whatever—from touching the WinSxS folder. That folder is Windows' own component store, and tampering with it is the most common cause of duplicate attribute errors. If you're desperate for disk space, use the built-in Disk Cleanup tool instead, and check the box for Windows Update Cleanup. It's safe. Also, always install updates from Microsoft directly, not from random download sites. Corrupt updates are another frequent source.

If you're a developer shipping your own SxS assemblies, validate your manifest with mt.exe -validate from the Windows SDK before deployment. A single duplicate attribute in your XML will trigger this exact error on user machines. Saves everyone a headache.