SD Card (very) slow to unmount on Mac OS X ?

This is due to spotlight indexing the card, especially when large stl files are on the card.

There are two solutions to fix this :

  • type this Terminal command when the SD card is mounted :
    mdutil -i off /Volumes/Smoothie/
  • and/or place an empty file named “.metadata_never_index” at the volume root. this can be done very fast with the following Terminal command :
    cd /Volumes/Smoothie/
    touch .metadata_never_index