If a user complains that their new Matlab install is running very slowly, consuming excessive amounts of memory and says 'processing' when they are not running any scripts then there may be a Java heap space problem. This is often accompanied by the following error in the Matlab console:
java.lang.OutOfMemoryError: GC overhead limit exceeded
A possible solution is to change the 'Enable Mathworks source control integration' setting from it's default value of enabled to 'none'. The setting is found under Home->Preferences->General- >Source.
According to Mathworks the default setting was from version 2014b onwards.