wordpress 3.4 unable to send e-mails

I have updated to 3.4 and now it is not possible to get a forgot password e-mail sent. I have several sites with wordpress installation and have tested before and after update and it is the 3.4 that makes it impossible to send e-mail, so I will not update on the rest of my sites untill this is fixed.
So now when users ask for a new password, they just get: The e-mail could not be sent. Possible reason: your host may have disabled the mail() function…

Any fix for this? or any idea when there will be a new update?