Waiting until a window exists in Applescript?
I seem to have fixed the main problem of the "waiting for window" issue. Apparently nested "tells" are not so good - so I solved this by specifying the process which owns a particular UI element:

repeat until window "Print" of process "Evernote" exists


Haven't solved putting the current date into the filename field of the "Save" sheet yet but tomorrow is another day! Here's the full script:

activate application "Evernote"
tell application "System Events"

    # Open the print dialog
    keystroke "p" using command down

    # Wait until the Print dialog opens before proceeding
    repeat until window "Print" of process "Evernote" exists
    end repeat

    click menu button "PDF" of window "Print" of process "Evernote"

    # Wait until the Menu button menu is created before proceeding
    repeat until exists menu item "Save as PDF…" of menu 1 of menu button "PDF" of window "Print" of process "Evernote"
    end repeat

    # Select the "Save as PDF" menu item
    click menu item "Save as PDF…" of menu 1 of menu button "PDF" of window "Print" of process "Evernote"

    # Wait until the Save dialog opens before proceeding
    repeat until exists window "Save" of process "Evernote"
    end repeat

    set theDate to current date

    #tell (current date) to get (it's month as integer) &amp; "-" &amp; day &amp; "-" &amp; (it's year as integer)
    #set the clipboard to result as text

    #set myDate to result as text
    #set the clipboard to "dog" as text
    #if (get (the clipboard) is not "") then
    #set value of text field 1 of sheet "Save" of process "Evernote" to get (the clipboard) &amp; ".pdf"
    #end if

    set value of text field of sheet "Save" of process "Evernote" to "dog" &amp; ".pdf"
    # Paste the contents of the clipboard in and Save
    # This is sorta hack; Probably best to leave the 'Save As" dialog open and let the user finish it off but I have a special purpose

    # click button "Save" of window "Save" of process "Evernote"


end tell