Some Firefox users have reported seeing a recurring new tab stating that installation of ABP is successful. This is a known issue and we are working with the developers at Mozilla to correct this. In the meantime, users have found success by uninstalling and reinstalling Adblock Plus via

If a reinstall does not correct the issue, try creating a new Firefox profile. You can create a new Firefox profile directly from the browser by folowing the steps below.

  1. Enter about:profiles into the browser's URL search bar.
  2. On the page, click Create a New Profile.
  3. Read the introduction and click Next / Continue.
  4. Enter a name for your new profile.
  5. Click Finish / Done.

For more information on managing profiles in Firefox, refer to this Mozilla support article.