Wanted: can the following OS fix be scripted and is anyone willing?
- Help a user find a designated folder created by Mail.app in the Finder e.g. 'Users/[your name]/Library/Mail/V2/Mailboxes/Repair.xmbox'.
- Then search through the folder structure and for each .emlx message just in that designated folder, open each email with TextEdit.app say, search for instances of 'base 64' and replace with '8bit' and save
This fix seems to address the issue being discussed here and obviously automating the steps would be a huge time saver.
MacBook Pro (15-inch Mid 2012), OS X Yosemite (10.10.2)