Fix ERROR_SXS_INVALID_ASSEMBLY_IDENTITY_ATTRIBUTE_NAME (0x00003700)

When you'll see this error

You're installing a game, a third-party driver, or a Windows update (especially on Windows 10 22H2 or Windows 11 23H2). Midway through, the installer bails out. The event log or a popup gives you ERROR_SXS_INVALID_ASSEMBLY_IDENTITY_ATTRIBUTE_NAME with code 0x00003700. I've seen this most often with older .NET Framework updates and some Creative or Realtek audio driver installers.

What's actually going wrong

Windows uses side-by-side (SxS) assemblies to manage shared DLLs and their versions. Each assembly has a manifest — an XML file that defines its identity attributes like name, version, and publicKeyToken. The error code 0x00003700 means the manifest has an attribute name that doesn't match the expected schema. Maybe it's misspelled (like pulicKeyToken instead of publicKeyToken), or an old tool generated a manifest with a custom attribute Windows no longer tolerates. The result? Windows refuses to load the assembly, and the installer fails.

Fix it in 4 steps

1. Run the System File Checker. Open an admin Command Prompt (right-click Start, select Command Prompt (Admin) or Terminal (Admin)). Type:

   sfc /scannow

   Let it finish. SFC replaces corrupt system files, including bad manifests in the WinSxS store. Takes about 15-20 minutes.
2. Follow up with DISM. If SFC finds errors or if the error persists, run DISM to fix the component store:

   DISM /Online /Cleanup-Image /RestoreHealth

   This checks the SxS store itself. Skip this step if SFC came back clean — you don't need it.
3. Reset Windows Update components. Corrupt update cache can throw this error too. In the same admin command prompt, run:

   net stop wuauserv
   net stop cryptSvc
   net stop bits
   net stop msiserver
   ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
   ren C:\Windows\System32\catroot2 catroot2.old
   net start wuauserv
   net start cryptSvc
   net start bits
   net start msiserver

   This wipes the update cache and forces a fresh download.
4. Re-register the Windows Installer. Sometimes the installer engine itself has a busted manifest. Run:

   msiexec /unregister
   msiexec /regserver

   Then reboot.

If it still fails

Check the Application event log (Event Viewer → Windows Logs → Application). Look for a warning or error from SideBySide. It often points you to the exact assembly path — something like C:\Windows\WinSxS\manifests\x86_microsoft.vc80.crt_1fc8b3b9a1e18e3b_8.0.50727.9679_none_deadbeef.manifest. That specific manifest has the bad attribute. You can sometimes delete that manifest (after backing it up) and let Windows rebuild it during the next update. But do that only if you're comfortable with a hex editor — I'd rather you just run a Windows 11 Repair Install using the Media Creation Tool. That's the nuclear option, but it fixes the whole SxS store cleanly.