If your Thunderbird crashes then you can use a backup by simply copying the data/profile folder to your new Thunderbird install. However, if you do not want to do that or do not have a backup you can try to manipulate a file usually called, "Prefs.js". Those .js files in the profile folder tend to be problematic and may stop your Thunderbird from loading properly.
What you can do is rename them to a number higher than the original name. For instance, "Prefs-1.js" and if there is an existing "Prefs-1.js" you would rename that to "Prefs.js". Then start Thunderbird.
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