Optimize CSS files - file not found

In the performance settings when Optimize CSS files is selected, I get a 404. The reports section shows a 404 for example sites/default/files/ctools/css/588b003a48050c4e59cbeba2b453cb92.css not found.

I have the site running on a Mac without any issues. It's on Ubuntu. It's not a permissions issue (files dir and sub dirs have chmod 777). And the directory does exist.

Any idea开发者_开发问答s? Or has any body else experienced this issue?

Make sure that the temp directory exists! Check Admin/File System for the setting. Especially if the DB was copied from another system (i.e. Windows), this may be set wrong.

If the temp directory doesn't exist, it can't compile the CSS files before copying them to the default/files/... directory

if your server is linux flush your cache, if your server is windows port to linux! :)