送信済みMailの文字化け - Apple サポートコミュニティ
: This string could be a "Stop Code" or a memory address identifier generated during a software crash or hardware failure. UCO1 E43VK 7z 004
: It may be a fragment of a UUEncoded or MIME attachment found in the header of an email. Recommendation UCO1 E43VK 7z 004