YSlow has been blocked for your protection.

Why was it blocked?
This add-on causes a high volume of Firefox crashes and other stability issues. Users should update to the latest version.
Who is affected?
Users of YSlow version 2.0.5 for Firefox 3.5.7 and later.
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.