Under Tools/Options/Composition/Spelling, which boxes are checked, and which Language is used? Press Alt if the Menu Bar with Tools is hidden. What is your version of TB, and which dictionaries, names and versions, are installed and enabled in Tools/Add-ons/Dictionaries?

Under Tools/Options/Composition/Spelling, the second box is checked: "Enable spell check as you type". Language is English (United States). My version is the 68.5.0. Installed dictionaries: - English United States Dictionary by Jorg K, 68.0 - German Dictionary by Kairo, 2.0.6.1webext - Italian Dictioanry by Flod, 5.0.0.1webext

I fixed mine, here's what I did:

1. Updated Thunderbird to 68.6.0
2. Removed the dictionary
3. Reinstalled the dictionary
4. Restarted Thunderbird

Note: In my case, after step 1 above, but before the other steps, the Language field was empty and non-responsive (greyed out) under Tools > Options > Composition > Spelling, despite having a dictionary installed under Tools > Add-ons > Dictionaries. After steps 2-4, the Language drop down was back to being active and was automatically set to the dictionary/language that I reinstalled.

I've followed your steps, but it didn't work. I tried those steps many times also with the other updates but it didn't help. In my case, after your step 1, the language field was perfectly working. Any other hint? Thanks a lot

I wonder if in this case where all the dictionaries and settings are correct in TB, but spellcheck doesn't work, is due to an external spellchecker, perhaps part of a word processing app, that is interfering. This happens with external password managers that are included with some security suites, as they block access to TB's built-in password manager.

Try also safe mode (Help/Restart with add-ons disabled). If you have the EN-US version of TB, you should still have the EN-US English spellchecker available in safe mode, there being no need for an additional EN-US dictionary. If that works, see if you can add other non-EN dictionaries.

https://support.mozilla.org/en-US/questions/1269172

Safe mode doesn't help. I have the Italian version of TB and if I start in safe mode, spell checker doesn't work anyway. Do you think the Microsoft word spell checker could interfere?

michste93 said

Safe mode doesn't help. I have the Italian version of TB and if I start in safe mode, spell checker doesn't work anyway. Do you think the Microsoft word spell checker could interfere?

One way to tell: disable it or exclude TB and see if it makes a difference. I'm inclined to believe this is not a TB issue, otherwise the forum would be deluged with complaints about spell checking. The Italian dictionary works fine here in the EN-US TB 68 (see picture).

michste93 said

I've followed your steps, but it didn't work. I tried those steps many times also with the other updates but it didn't help. In my case, after your step 1, the language field was perfectly working. Any other hint? Thanks a lot

You could also create a new Thunderbird profile, add one of your accounts, install the dictionaries and see if the problem manifests. If it doesn't, then something is messed up in your old profile.