Wrong calculation of folder size by Windows


I noticed today that my Windows system does not properly calculate folder sizes.

I'm actually trying to make a backup of all my personal and work content. When I check the whole backup folder size under properties, It shows me around 10 Gb. But when I open this big folder and select a subfolder, It show me 30 Gb... This is kind of really annoying and I think it's a major issue Microsoft should fix ASAP.

I would like to say (because I didn't find anywhere else to post it) that in my opinion, Microsoft lacks ways of collecting feedback from his clients. There is nowhere we can manually report bugs and crashes.

In any ways, I think that showing correct folder sizes is a really basic task that an Operating System should be able to do. Such a bug is inacceptable for a leader like Microsoft, and I honestly consider going along with Apple if this issue does not get quickly fixed. My computer will soon need to be changed in anyways.

Meanwhile, if some of you guys have found ways to go around this major issue, feel free to share them :). Thank you!

Here is my technical information :

Intel Core i7-3720QM 2.60 GHz

64 bits

Windows 10 family version 1803

Installed on 2018-06-20

O.S. version 17134.112

Many thanks is advance,


Hi Antoine_795,

It is widely reported that version 1803 of Windows 10 has introduced a bug into Explorer.exe

It is because it cannot read the metadata of files correctly, it mixes up the size and dimensions for example

Therefore it cannot calculate the size of a folder, especially if it has sub-folders, it also cannot calculate the spare space on a hard drive . . .

In the meantime, while we are waiting for Microsoft to fix this bug:

Click the link below to download a small free utility called Treesize - it is a great utility . . .

Using that tool, you will instantly see the size of all folders (always missing form File Explorer) and where space is being used on your hard drive . . .


Standard Disclaimer: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.

Power to the Developer!

MSI GV72 - 17.3", i7-8750H (Hex Core), 32GB DDR4, 4GB GeForce GTX 1050 Ti, 256GB NVMe M2, 2TB HDD

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Last updated June 24, 2020 Views 40,777 Applies to: