Finally I decided to email, hoping for support. I have been using TB for years, and I was very happy, allowing me to have several accounts, and it did work very well till last september, when one of the place where I work *Karolinska Institutet* moved to MFA using OFFICE365. Thunderbird was not authorized anylonger and I had to install OWL. I also had two email accounts on google. Since september therefore, in a regular and frustrating way, I keep losing the email tree when I open thunderbird, meaning all of sudden one or more than account do not show up anymore, or if they show up at starts sometime some of the folders are missing. The only option I have is to first remove the folders in the profile and they reinstall the account. Also for this reason, I try to have constantly TB open, but this is not ideal as it uses a lot of memory. My inbox's sizes are fairly large, could that be a concurrent cause of the instability, if so shall I move the emails locally (which I do not want) or would be better (of course would be nice to delete some) to create several subfolders in the root? [email removed from public]