Thread:Project:Support desk/Error creating thumbnail: Unable to run external programs, proc open() is disabled. Error code: 1/reply

MediaWiki in fact needs the proc_open function while it is running some external programs. Basically this code could also be changed to use another function, e.g. exec, but if your host believes he cannot create a secure setup with proc_open enabled, then he will most likely tell you the same for any function, which runs external programs.

For the thumbnail creation you might get it solved by setting

$wgUseImageMagick = false;

in LocalSettings.php. MediaWiki will then no longer use ImageMagick to create thumbnails. Anyway, even if that works, it is not a solution, but only a workaround.