After further investigation, we’ve seen that the in-product update results in a corrupted Info.plist file, rather than a corrupted MyEclipse executable. The resultant Info.plist file has every element duplicated, so it is quite easy to fix, if you haven’t already repaired the install via the CI 15 installer, or by re-installing.
The Info.plist file is found by right clicking on the MyEclipse app, in the installation folder, and selecting “Show package contents”. Now open the Contents folder and edit the Info.plist file, removing all duplicate lines. Save the edits and the MyEclipse application can now be run.