the home directory on a Mac is the one showing the House icon. If you’ve run the macro, you will find a folder there named “TextFiles”. It contains, just for the purpose of demonstration, 14 text files that are named:
vesti export_0.tif_1Veneer_Komposit.txt … to
… vesti export_13.tif_14Veneer_Komposit.txt
Now, if slice 13 of the example stack is currently visible, the message is shown, because there is a text file containing number 13 in the folder named “TextFiles”.
If the currently visible slice of the example stack is 15 then the message will not be shown. To test this, you must change the second line of my macro from
setSlice( 13 );
setSlice( 15 );