Messages when opened in I.E show up as blank with no message body or headers being displayed. This can happen to some or more then few messages.
In AM 4.6 + new RTF HTML Converter is Implemented which has issues with certain characters leading up to incomplete rendering of text in message and headers resulting in
Blank messages in I.E
Add General Item Entry in "ArchiveManager Configuration Editor"
RTF HTML Converter: value of 1 and IISRESET