How do you open a labview 10 vi with labview 9. I have the core 2 course exercises but they are from version 10 and I am running version 9.
You can only open VIs that are saved in a version of the same or lower version of the LabVIEW you are using to open them. There is no way you can open a LV2010 VI in LV2009.
However, if it is YOU that is sharing it, you can use LabVIEW 2010 to save the VI to LV 2009 (Go to File -> Save for Previous Version) and save it to LV 2009. You will then be able to use LV 2009 or higher to open the VI.
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You need to open in LabVIEW 2010 and do a Save for Previous Version for LabVIEW 9.
If you don't have access to LabVIEW 2010, then you can post your VI's in the downconvert thread (shown at the top of the LabVIEW board). State what version you have and what version you would like, and someone will downconvert it for you. Be sure to mark their message with a Kudo as thanks.