It's coded to automatically disable the start page if it crashes on startup. It's odd it doesn't detect it. Is this still present in r80.2?
You can work around the preferences dialog disabling it by manually setting the registry key 'HideStartPage' to the DWORD 1 in:
HKEY_CURRENT_USER\Software\Scirra\Construct2\Preferences
Does that fix it? If not it must be something else instead of the start page.