Perplexing mismatch between properties of folder and its backup

robst247 · 31 Jul 2018

I'm running 64-bit Windows 10 version 1803 on my ASUS X750JA laptop. Recently, I've noticed that after backing up files, the Windows Explorer 'Properties' for original and backup folders are quite different.

Today, for example, I copied the folder containing all my documents (i.e. not audio, photo or video files) from the D partition of my SSD to a USB stick, both NTFS formatted.

'Properties' for the original folder (on SSD):

Size: 9.52 GB (10,229,272,784 bytes)
Size on disk: 9.56 GB (10,272,018,432 bytes)
Contains: 19,916 Files, 1,977 Folders

Properties for the backup folder (simply created by copying and pasting the original folder to the USB stick):

Size: 9.52 GB (10,229,114,630 bytes)
Size on disk: 9.53 GB (10,236,719,104 bytes)
Contains: 19,897 Files, 1,977 Folders

How can there be such a large discrepancy (19 files and 35,299,328 bytes)?

Surely there should be no difference. That's the way it used to be. Please explain

bro67 · 01 Aug 2018

Because of the fact that you are using a USB stick for the files and it is going to be set at a different size in how its file table handles data, compared to your SSD. Simple apples and oranges that have been around since the first data storage device was created. A USB stick will use smaller clusters vs a SSD or even Platter Hard Drive will use larger clusters. NTFS - Wikipedia

eLPuSHeR · 01 Aug 2018

But there are some files missing on destination (19). Are they hidden files or something?

dalchina · 01 Aug 2018

If you wished to try to identify the differences between source and copy, you could try this free program:
WinMerge

Basically you browse to one folder in the left pane, the other in the right, and you get a list showing which is unique in each.

Not the tidiest of GUI's by some way, but hey, it's free.

Bree · 01 Aug 2018

eLPuSHeR said:

But there are some files missing on destination (19). Are they hidden files or something?

Very likely. If you had File Explorer set to not show hidden files (its default) then a copy-and-paste wouldn't have copied them.

Was it your Documents folder you copied? If so, open a Command Prompt (an ordinary one, not an admin one) then type the command...

dir documents\*.* /s /a:h

I suspect you will find a total of 19 files listed, most if not all being 'desktop.ini'.

robst247 · 01 Aug 2018

Thanks, Dalchina. WinMerge works perfectly and reveals that the ACTUAL difference is only one file, desktop.ini, in the original folder.

Since posting my original question, I've discovered that this problem of Windows Explorer miscalculating folder sizes seems to have emerged following the update of Windows 10 to version 1803 and is widely reported in forums, for example here: Incorrect folder sizes reported in build 17134.1

robst247 · 01 Aug 2018

bro67 said:

Because of the fact that you are using a USB stick for the files and it is going to be set at a different size in how its file table handles data, compared to your SSD. Simple apples and oranges that have been around since the first data storage device was created. A USB stick will use smaller clusters vs a SSD or even Platter Hard Drive will use larger clusters. NTFS - Wikipedia

But this problem also occurs when I copy a folder from one platter hard drive to another. It's a bug in Windows Explorer that has emerged since Windows 10 was updated to version 1803. See my post below.

dalchina · 01 Aug 2018

It might be interesting to see what a 3rd party file manager e.g. Free Commander, XYplorer (not free) made of the file number difference...
Downloads

robst247 · 01 Aug 2018

dalchina said:

It might be interesting to see what a 3rd party file manager e.g. Free Commander, XYplorer (not free) made of the file number difference...
Downloads

OK, thanks. I'll give Free Commander a try.

eLPuSHeR · 01 Aug 2018

I have the paid version of Total Commander. I cannot live without it. Windows File Explorer is so clumsy. Free Commander is nice too.