The documentation for the writexl function includes this summary of its arguments
write_xlsx(x,path = tempfile(fileext = ".xlsx"),col_names = TRUE,
format_headers = TRUE,use_zip64 = FALSE)
The argument x is the data frame you are saving, which is div1 in your case. You have given the path argument as
"C:\\Users\\Utilisateur\\Desktop\\TEST.xlsx"
but if you do not provide it, the function will use the result of
tempfile(fileext = ".xlsx")
That produces a random file name with the .xlsx extension. I just ran
tempfile(fileext = ".xlsx") on my system with the following result.
tempfile(fileext = ".xlsx")
[1] "C:\\Users\\fjcc\\AppData\\Local\\Temp\\Rtmp6RY7Qz\\file5cd45e13857.xlsx"
so it provides a file as a sub folder of my AppData folder. If you run
writexl(div1)
do you get an error?