Testing: I'm using Windows OS 32bit and Thunderbird 52.5.0 I downloaded from here; https://addons.mozilla.org/en-GB/thunderbird/addon/show-address-only/

Downloaded to my 'Downloads' folder installed: Menu icon > Addons clicked on gear wheel icon and select 'Install addon from file selected the downloaded file and clicked on 'Open' restarted TB at the prompt enabled the 'Sender[@]' column All works ok.

Updated Thunderbird to version 52.5.2 restarted TB 'Sender[@]' column is still visible All works ok.

re: I've just downloaded Thunderbird 52.5.0 (64-bit) on a new machine

You do not mention what OS you are talking about.

Note: the 32-bit version will run on a 64-bit Windows.

I believe 64bit version is created for Linux and possibly MAC, but I was under the impression that 64bit for Windows was not available as yet.

http://kb.mozillazine.org/64_bit_builds quote: There aren't any official 64 bit builds of Thunderbird and SeaMonkey for Windows.

Additional: tracking of bug for 64bit implementation for Windows 64bit. https://bugzilla.mozilla.org/show_bug.cgi?id=634233

Thanks for the reply. Sorry about not mentioning the OS, using Ubuntu Linux and installed Thunderbird from the repository. Thanks for any guidance you can offer.

Linux has specific 64 and 32 bit builds, but it's rare for this to affect add-ons.

However, this particular add-on doesn't appear in the list of available add-ons in the Tools|Add-ons window, perhaps because it claims compatibility only up to TB V12.

https://addons.mozilla.org/en-US/thunderbird/addon/show-address-only/

I'd click on "download anyway" and see what happens. Then you can drag-and-drop the downloaded xpi file onto Thunderbird's Add-ons window, or use the button next to the search box in the Add-ons|Extensions window to install from file.

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

I have used this add-on in the past but found it disruptive. Most of my spam/junk is blatantly obvious and much of it is handled well by filtering such as the built-in junk controls or my email provider's tools. The little that remains can easily be screened by hovering over addresses and seeing what appears in the status bar. I find this easier than having to work out the sender from some rather non-descriptive email addresses.

I use another add-on to do the same sort of de-obfuscation, but in the mail header pane rather than in the inbox listing.

https://addons.mozilla.org/en-US/thunderbird/addon/eaimh/

Awesome! Thanks for the information. I'll give it a try.