Clicking on a link in an email may not open this link in the external browser.
Crash due to incompatibility with McAfee Anti-SPAM add-on. Add-on is blocked in 52.0.1
Background images not working and other issues related to embedded images when composing email
Large attachments may not be shown or saved correctly if the message is stored in an IMAP folder which is not synchronized for offline use. Workaround: Set preference browser.cache.memory.max_entry_size to the value of -1 (unlimited) and create integer preference browser.cache.memory.capacity with the value of 200000 (200 MB, 25 MB per message).
Large number of blank pages being printed under certain circumstances