Hooray for firsts If errors.txt is in the same dir as the .jar, i see nothing. I did run "java -verbose -jar llorxkspmodmanager.jar" and got no error. Here's the last few lines of output [Loaded com.apple.laf.AquaFileSystemModel$DoChangeContents from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar][Loaded com.apple.laf.AquaUtils$1 from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded java.util.Vector$1 from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded com.apple.laf.AquaFileChooserUI$DirOrAnyPanel from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded com.apple.laf.AquaFileChooserUI$OpenDirOrAnyPanel from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded com.apple.laf.AquaFileChooserUI$CustomFilePanel from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded com.apple.laf.AquaFileChooserUI$SaveFilePanel from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded sun.lwawt.macosx.CDropTarget from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded javax.swing.JLayer from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded sun.awt.LightweightFrame from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded sun.swing.JLightweightFrame from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] ^C[Loaded sun.misc.Signal$1 from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded java.lang.Shutdown from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] [Loaded java.lang.Shutdown$Lock from /Users/joerickwalder/Downloads/jre1.8.0_05.jre/Contents/Home/lib/rt.jar] You can see the ^C where i killed it because no window opened. Like i said, no apparent errors popped up in the output and a CLI run without -verbose doesn't output anything.