1. Ensure that you downloaded the extension from AdblockPlus.org OR Firefox Add-ons.
2. Ensure that your browser is on version 51 or higher. Follow the steps below to check your browser version.
   1. Open Firefox.
   2. Windows: Click the Firefox menu icon, select Help and then select About Firefox.
      Mac: From the Mac menu bar, click Firefox and select About Firefox.
      The About Firefox window opens.
      The version is displayed next to the Firefox icon. If your browser is out-of-date, Firefox will automatically start the update process.
3. Uninstall and reinstall Adblock Plus.
4. Receiving a 'corrupt download' or 'conflict with other extensions' error? Refer to this Mozilla article about the inability to install add-ons.
5. If you are still experiencing issues, try refreshing Firefox.

1. Ensure that you downloaded the extension from AdblockPlus.org.
2. Ensure that your browser is on version 6.0 or higher. Follow the steps below to check your browser version.
   1. Open Safari.
   2. From the Mac menu bar, click Safari and select About Safari.
      The About Safari window opens.
      The version is displayed below the Safari icon.
3. Uninstall and reinstall Adblock Plus.

1. Ensure that you downloaded the extension from Opera Add-ons.
2. Ensure that your browser is on version 28 or higher. Follow the steps below to check your browser version.
   1. Open Opera.
   2. Windows: Click the Opera menu icon and select About Opera.
      Mac: From the Mac menu bar, click Opera and select About Opera.
      The About Opera tab opens.
      The version is displayed below Version information.
      If your browser is out-of-date, Opera will automatically start the update process.
3. Uninstall and reinstall Adblock Plus.

1. Ensure that you downloaded the extension from AdblockPlus.org.
2. Ensure that your browser is on version 16.6 or higher. Follow the steps below to check your browser version.
   1. Open Yandex Browser.
   2. Click the Yandex Browser menu icon, hover over Advanced and select About Yandex Browser.
      The About tab opens.
      The version is displayed to the left of the Yandex.Browser icon.
3. Uninstall and reinstall Adblock Plus.

If you still cannot install Adblock Plus after trying these suggestions, please contact support@adblockplus.org.