Versions of Safari by default have security settings enabled to only accept cookies from the current site. When the CrossBrowserTesting.com Bookmarklet is launched, it sets and checks a third-party cookie for verifying your login and accessing the links.

There are two actions that you can take to avoid this issue:

1. Make sure you are logged in to CrossBrowserTesting.com in Safari before using the Bookmarklet on the sites you wish to test.
2. Change your security setting in Safari to always allow cookies. To do this, open Safari, click "Safari->Prefences", and select the "security" tab. Change your setting to "always" accept cookies as demonstrated in the screenshot below for Safari 4.0 or (or "never" block cookies on Safari 5.1). This is the recommended way for users who work in Safari as their primary browser. (Please read up on changing your security settings before making changes as CrossBrowserTesting.com is not liable for any issues this may cause.)