Why can't I open ADInstruments Simple Data File (*.adidat) with LabChart 7 for Mac?

Since LabChart 8, LabChart data files can be exported as ADInstruments Simple Data File (*.adidat), that is the file contains only "raw" data, no settings. However, LabChart 7 for Mac had reached its final version before the extension *.adidat was released, therefore it does not recognise this file as a valid LabChart file and hence can't be selected from the open dialog:
servlet.ImageServer?id=015w0000003Njs0&oid=00D20000000HncM
The workaround is to rename the file extension to *.adicht. For a single file you might want to select the file and open the info window (command+I), expand the Name & Extension field and edit the extension accordingly. 
servlet.ImageServer?id=015w0000003Njse&oid=00D20000000HncM
Close the info window and confirm you want to change the extension.
servlet.ImageServer?id=015w0000003NjtD&oid=00D20000000HncM
You can batch convert a whole folder of *.adidat files to *.adicht files using the attached applescript
Please note: although the file looks like an *.adicht file after conversion it hasn't preserved any settings: channel calculations like cyclic measurement or digital filters will not be preserved. If the original file had units conversion say to mmHg applied the converted file will display the mmHg values, but you can't undo the units conversion to see the original mV data. Also channel names and comments are part of the raw data format and will be transferred.