Wordpress Plugin Slider Revolution Error

There is the best solution :

1. List item
2. Go to revolution slider on the dashboard
3. Select your slider causing the problem
4. go to param slider
5. Scroll to problem handlings on the right
6. Select Troubleshooting
7. set option: Put JS Includes To Bodyoption to true.

That's it

You may need to update your theme and/or the Rev Slider plugin.

I found this happening today after updating the Autoptimize plugin. Turning off Javascript optimisation in the Autoptimize settings fixed the problem (though likely at the cost of some performance).

I have the same problem. I am not sure what cause this problem but I can share my workaround:

1. First you have to have FTP access to your WP folder
2. Deactivate Revolution Slider plugin
3. Use FTP and go to revslider/public/assets/assets/svg/ and download svg.zip file to your PC.
4. Unzip svg.zip. Grab all unzipped content and put it in uploads/revslider/assets/svg/ folder.(If in uploads/revslider folders assets and svg doesn't exist you have to create them manually).
5. Go to revslider/inludes/framework/ open base.class.php file and edit function public_folder_unzip():

Old code

 if($unzipfile === true){
 update_option('rs_public_version', RevSliderGlobals::SLIDER_REVISION); 
 }
 else{
 add_action('admin_notices', array('RevSliderBase', 'copy_notice'));
 }

New code

 if($unzipfile == true){
 update_option('rs_public_version', RevSliderGlobals::SLIDER_REVISION); 
 }
 else{
 add_action('admin_notices', array('RevSliderBase', 'copy_notice'));
 }

6. Save file changes.
7. Activate plugin.