> ## Documentation Index
> Fetch the complete documentation index at: https://docs.proofcore.io/llms.txt
> Use this file to discover all available pages before exploring further.

# UNSUPPORTED_PROCESSOR

If you receive the error message **"UNSUPPORTED\_PROCESSOR"** while attempting to load the software, it indicates a incompatibility with your operating system.

## Cause

<Warning>
  **Incompatible Windows Build**

  This error means your current Windows version is not supported. This typically happens if:

  * You are on a version of Windows that is too new (e.g., a brand new Insider Preview).
  * You recently installed a Windows Update that is not yet supported by the loader.
</Warning>

## Solution

To fix this, you must install a compatible version of Windows. We have a detailed guide on how to do this correctly.

<Card title="Windows Reinstallation Guide" icon="windows" href="/getting-started/windows-reinstall">
  Click here to view the guide on how to downgrade or reinstall a supported Windows version.
</Card>