IF Function not working on desktop app but OK online

[daveg_i_norge]

I've been using excel on and off for over 20 years. My problem is that a simple IF statement works online but not on my desktop app.

=IF(C4=C5, "True", "False") was created online without errors and works, C4=1, C5=2

When I create the same on the desktop app I get this

 I have the problem on both of my PC's. If I use the formula wizard I get the same error.

Any help would be appreciated.

Dave.

[#2]

@daveg_i_norge 

Try replacing comma with semicolon.

[#3]

@Detlef_Lewin thanks for a quick reply. I have tried ; and . and , this is driving me crazy. 
if I download the file created online and open it on the desktop app it functions correctly , if I try and edit the formula it errors with the same message as before. 

[#4]

@daveg_i_norge 

Press the Windows key+R to activate the Run dialog.

Type    control international   and press Enter or click OK.

Click Additional settings...

What is the List separator?

Activate the Currency tab.

What are the Decimal symbol and the Digit grouping symbol?

[#5]

@HansVogelaar Thanks for you reply

List separator: .

Decimal symbol: ,

Digit grouping: .

[#6 · Accepted solution]

@daveg_i_norge 

Thank you. Point is not a good choice for the List separator. I'd set it to semicolon ;

You can then use ; between the arguments of a formula:

=IF(C4=C5; "True"; "False")

[#7]

I was just working with that as you replied. Yes setting the List Separator to ; has solved the problem.
Thank you for your time .