If, when you try to run GIMP the logo begin to appear, but after a time nothing happen, maybe there is an issue with some plugins.
Just to be sure, run the MATE Terminal, and type "gimp". If you get a message like below, then this is the case:
(gimp:1492): GLib-GObject-CRITICAL **: 09:29:42.333: g_param_spec_internal: assertion 'g_param_spec_is_valid_name (name)' failed
(pagecurl:1549): LibGimpBase-WARNING **: 09:29:42.338: pagecurl: gimp_wire_read(): error
To temporarily fix the problem use the following procedure in the MATE Terminal (logged in as administrator):
mv pagecurl ..
chmod a-x pagecurl
Note: replace "pagecurl" with the name provided by the error message.
Then close the terminal and run Gimp again.
I will take care of the issue for the next version.