If you’ve ever had to share files with data between different countries, you know that this can be problematic. For example, in Greece and the Netherlands the number “one thousand three hundred comma five” is written as “1 dot 300 comma 5”, in the UK it’s written as “1 comma 000 dot 5”, in Switzerland as “1 apostrophe 000 comma 5” etc etc. Same goes for dates.

So if you write software that is meant to be used in different countries, you have to be very careful and test thoroughly. And even then, you can run into problems. Just today I managed to solved a very weird one: Dutch-formatted numbers in an Excel file with Swiss settings caused an error message which, on the face of it, had nothing to do with formatting.

But the strangest, incomprehensible, 100% bang-your-head-on-the-wall problem I had was around 2005. My team wrote software that was meant to be multi-cultural and was used in Greece, Cyprus, Malta, Portugal, Turkey, Brasil and China (I may have missed a country or two after all these years).

So at some point me and my manager had to fly to Cyprus to test the software on-site; we went to a few of our customers and tried it out. And we were getting very, very, very strange error messages when doing simple, tried-and-true stuff. For a while we were flabbergasted.

After tearing my hair out and troubleshooting like crazy for hours on end, I noticed something which, while unusual, at first sight had nothing to do with our problems: our customers in Cyprus had set their Windows regional settings to use a dot as the thousand separator (according to the Greek settings) and… a dot (again) as the decimal separator (according to the UK settings).

Having tried virtually everything I changed it, just for the hell of it. I think I tried the normal Greek settings at first. And, like magic, everything was fixed! No errors whatsoever, everything ran smoothly!

You can imagine my astonishment.

I also tried a different setting (UK) and it was fine. I switched it back to the “special” Cyprus setting, and, sure enough, the problem started again. Now that I knew what to look for, I discovered that our software was “confused” (threw an error) when trying to understand just what kind of number 1 dot 234 dot 05 is.