Hi, Have used Thunderbird on OSX for many many years, with many different accounts. (Had about 10+ accounts back in the days - phew!) Now - my main account is Gmail, but I also have an iCloud-account. These have been working well, but as of yesterday, I suddenly can't create or even see previously created folders on my iCloud account. They show up just fine if I log in with a browser (total is 7 sub-folders, Trash excluded). The really frustating thing is that I do in fact see three of the seven folders in Thunderbird. And this is after deleting the account with message data, and re-installing the account (and yes, using an app-specific password in my Apple ID settings). All folders shows up just fine in Mail.app - but for reasons (message filtering, etc) I really like to be able to use Thunderbird as my mail client on OSX. First screenshot: iCloud sub-folder list Second screenshot: Thunderbird sub-folder list Any help/tips/workarounds are greatly and humbly appreciated! TIA