TB by default saves 1x file per folder (e.g. MBox like) - This means depending on your storage configuration and how you use folders, potentially writing 100MB

TB by default saves 1x file per folder (e.g. MBox like) - This means depending on your storage configuration and how you use folders, potentially writing 100MB, 1G, 10G, etc. back to disk on folder content change. For batch processing though, I use the CLI tools - thunderbird is view/compose only (procmail/formail/archivemail/offlineimap,etc) I was hitting performance probs on bigger folders, and setup some more strict archiving to archive older mails to subfolders/zap offline using an 'archivemail' job, etc, and the problem went away, with TB being quite snappy. as I understand it there was some effort to support 1-file-per-email, which might be an option now, but this has it's problems too. Outlook has it's PST corruption hell... Basically, in my opinion, email is a pain, each client shows it differently, though I am admittedly not up to speed on Opera Mail.