When running 'Image > Properties...' on an image that already has a scaling in µm set, the macro recorder will issue a warning:
<<warning: the options string contains one or more non-ascii characters>>

I suggest a more intelligent handling by either changing the prefilled input field content or the recorded parameter to "um" when a previous µm scaling is detected.

Information about your version of Java:

  os.arch => amd64
  os.name => Windows 7
  os.version => 6.1
  java.version => 1.6.0_24
  java.vendor => Sun Microsystems Inc.
  java.runtime.name => Java(TM) SE Runtime Environment
  java.runtime.version => 1.6.0_24-b07
  java.vm.name => Java HotSpot(TM) 64-Bit Server VM
  java.vm.version => 19.1-b02
  java.vm.vendor => Sun Microsystems Inc.
  java.vm.info => mixed mode
  java.awt.graphicsenv => sun.awt.Win32GraphicsEnvironment
  java.specification.name => Java Platform API Specification
  java.specification.version => 1.6
  sun.cpu.endian => little
  sun.desktop => windows
  file.separator => \

The up-to-date check says: REMIND_LATER

Information relevant to JAVA_HOME related problems:

  JAVA_HOME is set to: C:\UTILIT~1\FIJI-D~1.APP/java/win64/jdk1.6.0_24//jre
  imagej.dir => C:\UTILIT~1\FIJI-D~1.APP

Information about the version of each plugin:

Activated update sites:
ImageJ: http://update.imagej.net/ (last check:20150618000647)
Fiji: http://fiji.sc/update/ (last check:20150617220654)