Can't Activate Thesis Theme Without it Breaking The Site – Please Help!!!

This is so weird.

I built my test site elsewhere and ready to deploy to existing site. That site currently has an ElegantThemes theme.

I uploaded a brand new thesis_184 and when I activate it I get a 404 Gnarly error breaking the site. Also, I can’t access wp-admin.php – really anything on the backend.

The moment I delete the thesis_184 folder, all is good again. Old theme loads up fine.

I have renamed plugin folder to plugins.hold just in case it was a plugin issue.

Any idea what’s going on? I’d really appreciate any and all help. Thanks in advance!!!