I'm on Ubuntu at work and my Windows laptop's at home but there's others who've ran into what I'm talking about:

https://answers.microsoft.com/en-us/windows/forum/windows_10...

Basically: You see one file size on a parent folder, and when you drill in further it changes. I'm surprised these explorers don't try to cache some of the info somehow.

This sounds like someone doesn't understand how Windows calculates folder sizes. It will never show the size unless you look at the folder properties; and even then, there's no indication when it's done calculating. It might be obvious sometimes because the number is continuously changing, but if it hits a lot of very small files, it won't visibly change for a while.

Edit: Actually, apparently there is a bug related to this in recent versions of Windows, but it's still a behavior that can happen even without a bug.

Ah. Though that's still opening the properties dialog, which is much rarer than browsing.

Also they're reporting that it only happens with full filenames over MAX_PATH, so it's a very different bug. The base idea of "show a continuously-increasing size until don't calculating" works fine