20050218 trunk When another process has locked an mbox file, and Thunderbird tries to write to that file, the user is prompted with a dialog that states that the write operation failed. So far so good. The problem is that the dialog then suggests to compact folders to free up disk space when, in fact, the problem has nothing to do with disk space. It left my initially thinking that the MSF or even the mail file itself had become corrupted. Perhaps it would be better to say that Thunderbird was unable to write to the file because another program is using it, or something to that effect.