[Johnny555]

Their initial need for Office was some soft of forecasting model that they needed to update for a large investor. That was a big spreadsheet that ran on Office for OSX if I remember correctly. After that, I don't know what specifically they needed to use, they had purchased some software that required Windows and Office.

[sho]

Call me cynical, but having been around the block a few times when I hear "need" and "require" my brain translates that to "want" and "it would be convenient if". I've done my share of forecasting for investors and am quite confident that there is nothing in any startup forecast that could conceivably "require" Windows. I mean, absolute worst case, just use SQL.

The CFO just preferred Windows, that's it, I'd bet money on it.

[Johnny555]

The requirement came from the investment house - they wanted data in the format they were accustomed to.

What was driving that requirement at the investment house doesn't matter, when the company that owns over 50% of your company wants something, you don't say "Hey, we don't want to buy a Windows license with your money, how about I send it to you in this similar, but different format and then you guys can figure out how to make it match what you're looking for?"

[kube-system]

IME what it means is that they have a bunch of processes built that specifically depend on it. It doesn't make it impossible to switch but depending on the scope could be financially or practically prohibitive to migrate. Maybe someone has 10 years of custom excel macros put together that are run every quarter, that would need to be migrated. To migrate you might not have the internal capacity and might need to hire external help to do it.