Error when trying to test Craft Pro on .dev I have a fresh Craft install set up locally at mysite.craft.dev. I would like to start building out the features offered by the pro license, but when I click the "Show me" link in the footer, I get "An unknown error occurred." 

I am seeing this error in craft.log: 
015/04/03 17:13:55 [error] [php] Cannot modify header information - headers already sent (/Users/aaron/Sites/mysite/craft/app/framework/web/CHttpRequest.php:1392)

In potentially related news, tasks do not seem to be behaving correctly.

Anyone ever experience this before? Any help is appreciated :)
I found a solution! I had my local environment setup with homebrew following this article's instructions. After looking at the php error logs, I uncommented always_populate_raw_post_data = -1 in the php.ini file found in /usr/local/etc/php/5.6.

I then restarted the brew services with brew services restart php56 (install brew services by tapping gapple/services with brew tap gapple/services) and restarted apache with apachectl restart. 

That did the trick!