set x to choose file with prompt "Sélectionnez un fichier .txt"
set dossier to choose folder
set manquant to ""
set myList to paragraphs of (read x as «class utf8»)
tell application "Finder" to tell folder dossier
repeat with i in myList
if not (exists item i) then set manquant to manquant & (contents of i) & return
end repeat
end tell
if manquant is not "" then
set x to "Fichiers manquant dans le dossier " & dossier & return & return & manquant
tell application "TextEdit"
make new document at end of documents with properties {text:x}
activate
end tell
else
activate
display dialog "Les fichiers sont tous présents" giving up after 4
end if