deletet the update and uploaded the back up

What theme were you using, you should be on the default theme when you update anyway? 

What version are you updating from?

did you have debug open?

did you look at the js console to see if there was a message?

Cant scroll where ?  what page?

sorry dave,,, i was stressing haha... it was the join page. i gonna try all again in a local machine. I will keep you updated

ok, no stress advised  :)   thanks

Jordi, have you managed to fix the issue?

Yes i did a complete new update after replace a backup.

thanks !