Several of the plugins I've installed keep disappearing.
These are usually those to do with SEO and Social sharing, such as WordPress SEO by Yoast, Squirrely SEO and Social Gallery Lite.
I tried reinstalling them, but get this error message:
Destination folder already exists. C:/DWASFiles/Sites/octariblog/VirtualDirectory0/site/wwwroot/wp-content/plugins/wordpress-seo/
What do I need to do to reinstall this plugin? And why do they keep disappearing?