@tdoolittle said:
How do I remove this extension from Sketchup2016?
Since it's a simple Plugin [rather than an Extension which would also have its own subfolder], you can simply find its RB file ' dimension_utilities.rb' and delete it.
Look in your Plugins folder...
This one-liner copy+pasted into the Ruby Console +<enter> will open your Plugins folder for you [it is in a folder-path that is hidden by default]:
UI.openURL("file:///#{Sketchup.find_support_file('Plugins')}")
Alternatively if you have the SketchUcation Toolset installed you can use its Plugins-Manager dialog to Disable any listed plugin-file that is being Loaded/Enabled - when SketchUp restarts it won't load, but you could always reinstate it if you so desired, OR in the same toolset - use its submenu item to 'Uninstall' that plugin in which case, thereafter it won't load or even appear in any of its Manager dialogs, but it could still be Reinstalled later, if desired - by using the same dialog...