I've been bitten byt this feature for too long and I don't understand it. I'm using Idea 7.0.2 final and working on a J2ME project. For whatever reason I get this error everytime I invoke the Idea builder. (Eg. Make before running a unit test or CtrlShiftF9). The error just says Error: duplicate entry: META-INF/MANIFEST.MF with no further ryhme, reason or explanation. We have an Ant build that generates our midlet's manifest file and to my knowledge there's nothing wrong with it. It's not associated with my project in any way and everything builds and runs just fine from the command line. I tried configuring a custom manifest file to no avail. I've looked at the manifest file that we generate and nothing stands out. Any ideas?