I’m trying to load plugins automatically by putting the plugins into mu-plugins folder. But if the plugin is put in a folder, it isn’t loaded. I tried some popular plugins such as W3 Total Cache, WordPress SEO By Yoast, but all of them are not loaded.
Does WordPress only loads plugins which are just single files in mu-plugins?
Does WordPress only loads plugins which are just single files in
mu-plugins?
No, they do not need to be single files but you cannot use plugins in their own subfolders as in the standard plugins/ folder.
The main plugin file (one with the specified plugin header info) has to be right there in mu-plugins/. Other files can be put in a subfolder and referenced from there.
I used it with my own plugins. I’ve never tried moving any robust plugin in there.
Also note that not all plugins are must-use-compatible
see http://codex.wordpress.org/Must_Use_Plugins#Caveats