iPhoto Stream

I had a tab on the left of Photos on my iMac that was "Photo Stream". This has vanished, poof. How do I get it back?

You are using the terms "iPhoto" (in the thread title) and "Photos" interchangeably. Since there's nothing about the specs of your Mac, you'll need to clarify a bit more what you're talking about. Neither iPhoto nor Photos has tabs, so I'm having to assume you're actually talking about albums on the left side of iPhoto -- would this be correct?

http://www.mac-forums.com/forums/news-community-announcements/313284-writing-quality-post.html

Mine disappeared and chas_m suggested running Onyx. It came back.