Adobe removed support for the Extension Manager in CC 2015, so you will need to manually install GuideGuide. There are some cases where installing GuideGuide into the Extension Manager may work, or appear to work, however these are unique and unreliable.
Download the zip file above and unzip it.
Launch Terminal and run this command to open the install folder (or open the folder yourself):
open /Library/Application\ Support/Adobe/CEP/extensions/
Copy the unzipped GuideGuide folder into the extensions folder. It should look like this.
Copy the unzipped GuideGuide folder to the appropriate directory.
Windows 64: C:\Program Files (x86)\Common Files\Adobe\CEP\extensions\
Windows 32: C:\Program Files\Common Files\Adobe\CEP\extensions\
If the Adobe\CEP\extensions folder does not exist, you can create it.
Restart Photoshop. You’ll find GuideGuide at Window > Extensions > GuideGuide
Ensure that you do not modify the GuideGuide folder. Doing so will cause a “The GuideGuide extension could not be loaded because it was not properly signed” error when you try to launch it.
Make sure that you have the Adobe Extension Manager installed, and that it is the same version (CS5,CS6,CC, etc) as your copy of Photoshop. Also be sure you download the version of GuideGuide that matches your copy of Photoshop.
Launch the Adobe Extension Manager.
Windows Users: You may need to run the Adobe Extension Manager as Administrator (right-click the Adobe Extension Manager icon and click “Run as Administrator”).
Click Install and navigate to the GuideGuide extension file (.zxp).
The Extension Manager will ask you to accept a disclaimer.
You should now be able to find GuideGuide at Window > Extensions > GuideGuide
GuideGuide creates guides based on your document or the selection.
The quick guide buttons let you add guides at the edges or midpoints of your document or selection.
$v = | ~ | 10px | $h = | 16px | | 20px | $v*5 | ~ | 20px | ( vFlp ) | 100px | $h* | ( hFlp )