just had this problem, and since it is not mentioned here, this is how I fixed it.
I noticed I was getting
PHP Fatal error: Maximum execution time of 30 seconds exceeded in /var/www/html/adinfablog/wp-content/plugins/ssh-sftp-updater-support/...
logs.
I updated the max_execution_time line from 30 to 120 in /etc/php.ini:
max_execution_time = 120
Then I restarted apache (on CentOS: apachectl restart) and it fixed it. It took a long time to update (6-7 minutes?) but I had a “top” command open and could see the httpd process was busy and doing things.
YMMV
Craig
