File Explorer reporting wrong size for some folders, Windows 10 v1809

As you can see from the images above, File Explorer reports that the Windows directory is 2.47GB in size, but if I check the size of one of the sub-directories in the Windows folder (in this case the WinSxS folder), it reports a size of 6.01GB. How can the Windows folder be only 2.47GB if just one of its sub-folders is 6.01GB? Clearly this isn't accurate, is anyone else experiencing this issue and is there a way to remedy it?

Yes, File Explorer will report the wrong size for WinSXS.

Determining the size of the Windows Component Store is complicated by the fact that many of the files are used by Windows from directories outside the Windows Component Store using a technique known as hard linking. In such cases, the files from a component version appear both inside and outside the Windows Component Store. By using hard linking Windows is able to appear to keep multiple copies of the same file without actually taking the added space for multiple copies.

...This tutorial will show you how to determine the actual size of the component store (WinSxS folder) and if cleanup is recommended in Windows 10.

Analyze Component Store (WinSxS folder) in Windows 10 | Tutorials

I see, however the point I was making was that older versions of Windows 10 would report more accurate sizes for these folders, even if I were to check the size of everything in C: including protected system files, the size that explorer reports would be less than what a disk space check would report for used space on that drive. I know for a fact that a fresh Windows 10 install will have the Windows folder at around 18.x GB. Microsoft seem to have broken something in a recent update.

mTaylor0248603 said:

I see, however the point I was making was that older versions of Windows 10 would report more accurate sizes for these folders...

No, File Explorer has always misreported WinSXS because of the hard links. It counts the size of each hard link, even though it is only one physical file with multiple references. The same effect is seen in Disk Clean up. It is not unknown for it to report 3.99TB can be cleaned up after a cumulative update. Here's an example of that from two years ago, so that would have been running version 1607.

I went to do a clean-up and backup before shutting down for the night and it claims I have 3.99TB of old Windows Update files. The fact I only have a 500gb SSD drive, I find that impossible.

Windows Update Clean-up files 3.99TB - Windows 10 Forums

But why is the Windows folder showing up as only 2.47 GB?