Have just spent 4 ABSOLUTELY FRUSTRATING hours dedicated to this one and only topic and comparing every big, small and tiny thing happening with another store that was working correctly.
As such I now have a result!!!!!!
Something this simple should not have to rely on 2 php configurations to make it work!!!!
J 2.5.11 / VM 2.2.20b
On my hosting server I turned Magic Quotes ON and Register Globals OFF.
Might be tricky to access your php.ini file for some but to me, this was the one change I made, did ANOTHER purchase and voila!!! The customer and the admin email popped through!
Let's know if this helps anyone else!
I am having the same problem.
I have sent the thread link and your post to my site hosts. Thanks for sharing.
At this stage I don't know what these parameters do or why this should make any difference but worth a try.
I will keep you posted regarding the result.
My host tech advises that those were already the default settings.
It seems I have a different problem.
I did a site migration after a rebranding. It changed the URL and of course the email addresses. I had to update the site path default but I can't remember which file I had to modify.
My latest theory is that there is an old email address in a configuration file somewhere that is preventing system notifications from being sent to me.
I was mistaken thinking that the emails were not getting to customers. That appears to be fine.