Why can't I open an experiment file with the extension .LTEXP that I created previously in LabAuthor.

The .LTEXP experiment file may have been written with a later version of LabAuthor than what is currently installed, and you will need to update to the latest version of LabAuthor to open this file for editting.  LabAuthor can be updated with the latest version of the LabTutor 4 Teaching Suite installer file, which is located HERE.

If you still cannot open the after updating, please contact your localADInstruments technical support.