HT203353 Safari extensions disappear when I quit the program?

Question

Why do Safari extensions disappear when I quit the program? They are all from the Apple extensions pages.  I started manually adding extensions because the Add This bar disappeared when I clicked the extensions off button and I couldn't find it to get it back. I liked Add This because it added an extra bar below the url box with the extensions in color. I tried to add the Pocket extension to Add This with a supposed installer from the web site but it disappeared when I clicked on it and didn't add it. Now when I add extensions from the Apple Safari extensions pages there are just little grey images on buttons beside the url box. I quit Safari at night and the next morning when I start the program the extensions are gone. They were all enabled which appears to be the default. Also want to know if Add This is no longer supported.

Answer 1

Back up all data before proceeding.
Launch the Keychain Access application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad and start typing the name.
Use the search box in the toolbar of the Keychain Access window to search for an item named "Safari Extensions List". If found, delete it. Quit Keychain Access.
Quit and relaunch Safari.