When switching your IIS application pool to 32-bit mode, the handler mappings for .html to be processed as classic ASP may stop working because IIS uses a separate 32-bit pipeline and module set (%SystemRoot%\SysWOW64\inetsrv) instead of the 64-bit one.

To fix this:

1. Reconfigure the handler mapping after enabling 32-bit mode. Go to Handler Mappings for your site or application in IIS Manager.

2. Ensure you're referencing the 32-bit asp.dll, which is typically located at:

   C:\Windows\SysWOW64\inetsrv\asp.dll

3. Make sure the application pool is set to Classic Managed Pipeline Mode if you're using classic ASP with custom extensions.

4. Also verify that ASP is enabled under “Turn Windows features on or off” > IIS > World Wide Web Services > Application Development Features.

This should restore .html to be processed as classic ASP under 32-bit mode.