By mistake I added comments to another thread about half an hour ago, so now I will post them here:
Strange thing happened...
I updated to 1.6.2, hit the button to start a backup, it changed to Starting Backup, and then died. That happened twice, with no backups done and no temporary files being created (checked with FileZilla).
Yet the third time around it worked, sort of :-)
It made the backup, but did not delete the .backup_running file and I am still waiting for the email. The back weights 16.7mb and I waited for about 15 minutes, so maybe it will still come in a while.
Still waiting for the email, so I think it just didn't go out at all.
Besides, I tried updating the other website mentioned before and after creating the backup (first try), when it tried to send it, WordPress failed:
Fatal error: Out of memory (allocated 61341696) (tried to allocate 20487392 bytes) in /home/ideariu/public_html/es/wp-includes/class-phpmailer.php on line 1495
Just in case it's useful, the URL at the moment of the crash was /wp-admin/tools.php?page=backupwordpress&action=hmbkp_backup_now.
The backup weighted 15mb.