Unable to use optimized view rebuild for view

I receive several of these messages regarding different databases. Has anybody seen this and know how to resolve?

Unable to sue optimized view rebuild for view (x) due to insufficient disk space at /(servername)/views.

Thanks,

Subject: Check your OS TEMP folder

Make sure you’ve got enough room on it. If that can’t be written to you’ll have that warning. Also check your INI for a something_TEMP_DIR setting and check that path too.