I followed all the steps, but it still did not work. Sorry. Please help.

Which Spanish dictionary? I see about 5 of them for different countries and they are not all created equal.

Given your profile set the tmezone to US pacific, I will guess it is the Mexican. You need to edit the XPI file to install it. It is just so old.

Which version of Thunderbird?

Thanks. I have tried several of the dictionaries and none work any more.

I am on version 65.0b2 (32-bit). I am on the beta channel if that makes a difference.

Also, it helps to read the release notes when using a beta. https://www.thunderbird.net/en-US/thunderbird/65.0beta/releasenotes/

I apologize, but I am still not finding the solution.

Would it be easier if I leave the Beta channel?

@sfhowes, I have clicked on your link, but that is for Firefox - I need this for Thunderbird.

If you can give me step by step instructions, I would greatly appreciate it.

@sfhowes, Thank you. The Mexican dictionary works.