Running out of swap and memory is one thing, although unlikely considering how much of that stuff we've got nowadays. I for instance have 8gb of main memory and

Running out of swap and memory is one thing, although unlikely considering how much of that stuff we've got nowadays. I for instance have 8gb of main memory and 10gb of swap space. 300mb are used after system boot (still too much). That leaves me with plenty of space to "waste" on temporary files in a tmpfs. The Linux FHS explicitly states "Programs must not assume that any files or directories in /tmp are preserved between invocations of the program." That's not only reboots. It's not meant to be used to store drafts or anything that you might want to reopen at a later time. That's what we've got /var/tmp for. The FHS specifies as follows: "The /var/tmp directory is made available for programs that require temporary files or directories that are preserved between system reboots. Therefore, data stored in /var/tmp is more persistent than data in /tmp". Tmpfs isn't harmful because of this, it's the default mutt configuration which is broken. If developers would have adhered to the standard the problem wouldn't exist. Since programs should adhere to the standard, because decisions like the one in question are made upon it, they should be reviewed and their default configurations should be changed in order to fix this issue.