Whenever an image is opened and the channels tool is opened, ImageJ freezes upon toggling the options (composite/grayscale/colors). The only way to quit ImageJ at this point is to do Force Quit. This happens every time, and does not seem to be file type dependent.

Information about your version of Java:

  os.arch => x86_64
  os.name => Mac OS X
  os.version => 10.10.4
  java.version => 1.8.0_51
  java.vendor => Oracle Corporation
  java.runtime.name => Java(TM) SE Runtime Environment
  java.runtime.version => 1.8.0_51-b16
  java.vm.name => Java HotSpot(TM) 64-Bit Server VM
  java.vm.version => 25.51-b03
  java.vm.vendor => Oracle Corporation
  java.vm.info => mixed mode
  java.awt.graphicsenv => sun.awt.CGraphicsEnvironment
  java.specification.name => Java Platform API Specification
  java.specification.version => 1.8
  sun.cpu.endian => little
  sun.desktop => null
  file.separator => /

The up-to-date check says: UP_TO_DATE

Information relevant to JAVA_HOME related problems:

  JAVA_HOME is set to: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/
  imagej.dir => /Users/gayounglee/Desktop/Fiji.app

Information about the version of each plugin:

Activated update sites:
ImageJ: http://update.imagej.net/ (last check:20150720121756)
Fiji: http://fiji.sc/update/ (last check:20150721112030)

Files not up-to-date:
  7f0d443a (MODIFIED) 20150721181103 Contents/Info.plist
  6d15bb1c (MODIFIED) 20150721182012 jars/ij-1.49v.jar