Quick answer
Error 3247440388 (hex 0xC1900204) means the Windows 11 you're installing doesn't match your current edition. Check your edition (Settings → System → About) and use an installer of the same edition — or use the Windows 11 Installation Assistant, which matches it for you automatically.
WHY IT HAPPENS
An upgrade has to migrate like-for-like.
An in-place upgrade keeps your apps and files, so Windows insists on migrating to the same edition (Home → Home, Pro → Pro), the same language, and the same architecture (x64). If you mount an ISO and pick the wrong edition — or use media that doesn't match your current install — setup can't migrate and stops with 0xC1900204, shown as error code 3247440388.
THE FIX
Work through these in order.
- Check your current edition and languageOpen Settings → System → About (or press Win + R and run winver). Note whether you're on Home or Pro, and your display language — you'll match the installer to this.
- Use the Windows 11 Installation AssistantDownload the Windows 11 Installation Assistant from Microsoft and run it. It upgrades in place and matches your edition and language automatically — this is the easiest fix and it sidesteps the mismatch entirely.
- If using an ISO, pick the matching editionWhen you run setup from an ISO, choose the edition that matches what you found in step 1 — don't select Home if you're on Pro — and confirm the correct language and x64 architecture. A mismatch here is what produces the error.
- Confirm the PC meets Windows 11 requirementsRun Microsoft's PC Health Check app to confirm TPM 2.0 and Secure Boot are enabled and supported. This rules out a separate blocker before you retry.
- Free up disk space and clean old install filesRun Disk Cleanup → Clean up system files and remove Previous Windows installation(s) and temporary files. Setup needs free space, and stale install files from a failed attempt can trip it up.
- Retry — and if it still fails, hand it to ITRun the upgrade again. If it still stops, note the exact current edition vs target edition (e.g. "Windows 10 Pro x64 English → tried Windows 11 Home") and pass that to IT so they can supply the correct media.
On a work or managed device? The Windows edition and feature upgrades are usually controlled centrally by your IT team — through licensing, imaging and update policies. Check with IT before forcing an upgrade so the edition and licensing stay correct, rather than accidentally landing on the wrong edition and having to redo it.
