This post is to answer a common question we've been receiving since we put out v4.5.2: what happened to my channels from a previous DRS after I run a new DRS? This is due to iolite clearing out all intermediate and output channels when you click the Crunch button. In earlier versions, by default, channels previously calculated would remain. However we found that people were not aware of the consequences of this being the default. For example, if you calculated your trace element concentrations using the semi-quant method, you would get (for example) a Ca43_ppm channel. However, if you then decided to use Ca as your internal standard, and re-crunched your DRS, it would leave the Ca43_ppm channel there (even though normally you don't get a ppm channel for your Int Std). This is what we call an 'orphaned' channel because it's not really current or valid and it was causing many beginners trouble.
If you don't want all intermediate and output channels to be cleared when you click the Crunch button, you can simply uncheck this option in the DRS View. There is a wrench icon in the top right that if you click, you'll see the option "Clear channels before crunch". Uncheck this option to allow channels to persist.
If you have any questions about this, please feel free to respond to this post.