Missing "Clean URLs" option I have a new installation of Drupal 7. I was having a problem with administrative overlay URLs having URL encodings in them, which I asked about here. Another user suggested I confirm that I have clean URLs enabled. 

When I went to Home » Administration » Configuration » Search and metadata » Cleanr URLs, all I see is this: 


  Use URLs like example.com/user instead of example.com/?q=user. If you are directed to a Page not found (404) error after testing for clean URLs, see the online handbook.


The message was followed by the button, "Run the Clean URL test." that seems to do nothing: The browser tells me it's loading something from the site, but the page doesn't change. 

I have no options to enable or disable clean URLs.
I'm pretty sure it's disabled, because when I go to website.com/user, I get a 404. 

How can I troubleshoot this?
This is a known problem in Drupal 7. The "Run the Clean URL test" button does not behave like that page says it does, and this can be very confusing. Please see "Run the clean URL test" UX is broken; basically, what it comes down to is that the logic and UX of that page is broken, but the clean URL system itself (ie. the part in Drupal core that makes clean URLs work) does not contain any (known) bugs.

If you cannot enable clean URLs (you don't see the checkbox to enable it), this means that a test has already been run, it returned a negative result, and you should check your server configuration. See drupal.org - Clean URLs for documentation.

PS. If you can, test the patch from comment #87. This patch will improve the UX on the clean url's page, but it will not solve problems with an incompatible server configuration.