Notice: this information was written when Microthemer version 2 was current. On Dec 26th, 2014 version 3 was released with a completely new interface. Some of the information may be redundant, but as much of
the functionality remains the same in version 3 we haven't deleted this post.
Found this message today after upgrading to 2.4.7 but it could have been there earlier.
Warning: ob_start() [ref.outcontrol]: output handler ‘ob_gzhandler’ cannot be used twice in /home/fusionth/public_html/wp-content/plugins/microthemer/tvr-microthemer.php on line 240
This should be fairly easy to fix. Just go to the Microthemer > Preferences page and set the “Gzip Microthemer UI Page” option to No. This option speeds up the Microthemer UI page a bit when it first loads, but doesn’t provide any benefits past that.
If that doesn’t solve your problem please write back here and I will investigate things further in the morning.
