If I am composing a message, and add a large attachment (e.g. 1 MB), from that time forward every time Thunderbird autosaves the message to drafts, the program completely freezes for a period of many seconds (say 10 to 60 seconds). No keyboard input is displayed during this time. The period of the freeze seems to be proportional to the size of the attachment(s). This is extremely irritating! I am currently using TB 24.6.0 on XP, but this problem started happening maybe 6 or 12 months ago. It seems that something has changed with the way that TB handles attachments, and apparently each time it autosaves a draft it does a lot of work, and it drives the CPU load to 100% while it does it. This is driving me crazy.