About Lost Storage Space, MsgQueue files and built-in storage
The MsgQueue files you see aren´t the problem. They may look like they´re
that big, but that´s because the OS doesn´t know how to correctly report the
size of the special queue files. They´re much much smaller.
Even if you have an SD card installed, that doesn´t change the amount of
built-in storage that´s available. You have to go and uninstall the
applications you put into internal storage (either through ActiveSync or via
Settings > Remove Programs on the device), then re-install them and select
"Storage Card" as the install location when you are prompted.
