Drupal may give you the error message “The jQuery UI plugin is missing. Download and extract it into the sites/all/libraries directory. Rename the extracted folder to jquery.ui” from the Status Report (../admin/reports/status ) page.
If should direct you to the page to download it from (if it’s a nice Drupal 🙂 ) (linked above), and if you read closely it tells you once you have downloaded it, that it needs to be installed into the /sites/all/libraries folder.
If you’re like me, you’ll miss this crucial step, so just in case, I will lead you through the easy steps of how to do that here.
So, first, download the package! There should be a link, but the latest at the time of writing this article is 1.6 found here.I choose the most recent, always, which looks like it’s over 2 years old, so chances are it won’t change.
Once this is downloaded, you extract the zip file (right click -> extract here) and copy it into your folder located in: ../sites/all/libraries
Now, rename the folder to jquery.ui, which should give you something similar to:
sitesalllibrariesjquery.ui
Inside of which is all your files. Your structure should now look similar to this:
Once this is done, you should be able to refresh your pages status report ( ../admin/reports/status ) and it should show that you are now running the jQuery.ui!
Good luck!