Many will tell you that it will not work.
But that’s only partially true. If you REALLY want to use MS CRM from Firefox, here are two tips you might not have thought of.
First, you can try skipping directly to the full URL //loader.aspx">http://<server>/<organization>/loader.aspx. This will skip the browser check. You will see the CRM, but many things will be broken.
The real solution is to use IE Tab Firefox Add-in. It will open specified URLs in Firefox using IE renderer. You’ll notice a subtle icon in lower right corner but that’s it! You’ll get the best of both worlds.
Here is a screenshot: