WordPress version: 3.5.1
WordPress SEO version: 1.4.*
I did this: I upgraded WordPress SEO from 1.3.4.4 to 1.4.3
I expected the plugin to do this: Not break Contact Form 7 (v 3.3.3)
Instead it did this: All of the forms on my site disappeared.
I then tried each version of WordPress SEO and the last version that worked with Contact Form 7 was 1.3.4.4 so I've left it at that version.