.dat file to xlsxl

[Makada]

Mm, so i cant get it to work with Excel outputfile.
While it works ok with a .dat file:

import time
import schedule    
     
def task1():  
    existingLines = set(line.strip() for line in open("C:\\Users\\Makada\\Desktop\\CR1000_Table1 - kopie.dat"))
    outfile = open("C:\\Users\\Makada\\Desktop\\CR1000_Table1 - kopie.dat", "a+")
    for content in open("C:\\Campbellsci\\LoggerNet\\CR1000_Table1.dat", "r"):
        if content.strip() not in existingLines: # to void duplicate lines
            outfile.write(content)
            existingLines.add(content)
    outfile.close()
     
schedule.every().minute.at(":01").do(task1)  
 
while True:
    schedule.run_pending()
    time.sleep(1)
refresh()

I really like the possibilities of Excel for simple data correction and graphing.