Use the latest general release of 52.8 until the add on is updated. Your add on choices are limited when you chose to run beta software.

thank you i re-loaded 52.8 but it doesnt work for that either...

Adding search engines to TB (>45) is a bit more involved, but the instructions here work in TB 52. The changes are retained when you update to TB 60.

To add Google, create a google.xml file with a text editor and paste the content that I have posted here.

Use the same method for DuckDuckGo (xml content).

You can't install the Google Search for Thunderbird add-on from within recent Thunderbird because it says "Works with Thunderbird 11.0 - 31.*" .

However, as "coast40" writes in a review I could install the add-on manually in Thunderbird 52.9.1 for Windows without having to edit XML files. Visit the Google Search for Thunderbird add-on page in your browser, click [Download Now] and save the .xpi file. In Thunderbird press Alt+T to bring up the menu bar, Tools > Add-ons > Extensions, click gearwheel > Install Add-on from File..., navigate to the .xpi you downloaded and Open, confirm the warning and Install, and restart Thunderbird. That automatically changed the search option when you right-click on selected text in a message to 'Search Google for ...', I didn't have to go to Tools > Options > General > Default Search Engine to make it the default.