Here is how I worked around this:
* close thunderbird, make sure it's not running in the background
* `rsync -raxPHAX ~/.thunderbird/ ~/snap/thunderbird/common/.thunderbird/`
* edit `~/snap/thunderbird/common/.thunderbird/profiles.ini` to make sure the only profile listed here is the one with the data (the biggest folder in `~/snap/thunderbird/common/.thunderbird/`)
* run thunderbird
So far, everything seems to be in order, including contacts, calendars on multiple accounts, sieve filter and message redirect plugins.
Here is how I worked around this: thunderbird/ common/ .thunderbird/ ` thunderbird/ common/ .thunderbird/ profiles. ini` to make sure the only profile listed here is the one with the data (the biggest folder in `~/snap/ thunderbird/ common/ .thunderbird/ `)
* close thunderbird, make sure it's not running in the background
* `rsync -raxPHAX ~/.thunderbird/ ~/snap/
* edit `~/snap/
* run thunderbird
So far, everything seems to be in order, including contacts, calendars on multiple accounts, sieve filter and message redirect plugins.