Exported csv file from strategy tester result cannot be edited in excel

Stam11  
Hello! I have a problem and I would be really glad if someone can find me the solution that I am trying to find for 1hour and a half now but without success. I have made a backtest in the strategy tester in MT5 of an EA that I have coded and I have exported the graph result into a .csv file in order to be able to further analyse the data. But when i open the .csv file in excel I cannot edit the values in the cells. For example, I want to subtract a number from a cell, and when I do that I get the #VALUE! error. I have tried converting the data in the cells from text to number but it doesn't work. I have also tried converting the .csv file to .xlsx with an online converter but still the problem persists. Is there a setting that I must configure inside of the MT5 platform? The files do not seem to be 'protected' or locked. I must inform you that I am using an iMac. Thank you in advance!!