Thunderbird works quickly for me even with multiple IMAP accounts, much faster than any webmail solution. Try compacting your folders: https://support.mozilla

Thunderbird works quickly for me even with multiple IMAP accounts, much faster than any webmail solution. Try compacting your folders: https://support.mozilla.org/en-US/kb/compacting-folders https://support.mozilla.org/en-US/kb/compacting-folders