I get this error twice per day. If I turned off minify cache I get this sometimes, maybe 1 time per week.
"Unfortunately, an error occurred while creating the minify cache. Please check your settings to ensure your site is working as intended."
My setting is - http://monosnap.com/image/Q7IKN8UpeEWkA2UW3ShpQCFsiyloIM.png
If I set "Manual mode" Minify cache does not work and is not created.