We’re seeing several reports each week from users whose sent mail is converted to Chinese characters or question marks.
One frequent cause is the antispam program BullGuard. If you are using this program, check for updates and if the problem continues, uninstall or disable it.
Other email scanners may cause problems, especially any that add a disclaimer to the message.
Published March 17, 2009. Last updated on June 21, 2011.