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Ask The Performance Team
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Viewing Folder Sizes in Explorer

CraigMarcho's avatar
CraigMarcho
Icon for Microsoft rankMicrosoft
Mar 16, 2019
First published on TECHNET on May 08, 2009

Good morning AskPerf.  Today’s post is a very short one, but it does address one of our most common Shell / Windows UI questions.  That question is, “Why can’t I see the size of folders in Windows Explorer?”  The simple answer is that the behavior is by design.  You can view the size of folders by hovering over the folders in Windows Explorer (as shown below):

The primary reason why the Windows UI does not provide this functionality is performance.  Every time you navigate through a folder structure in Windows Explorer, the OS would have to perform a recursive scan of the subfolder structure within each folder to get the file and folder sizes and add them up.  This would create significant processor overhead – especially if you think about scenarios (home folders for example), where the nested directory structure for each user may be several levels deep and consist of thousands of files and folders.  Extend the scenario from the local machine and add in users who are browsing through a directory structure across the network and the performance hit would grow exponentially.

The hover behavior above is governed by the “Display file size information in folder tips” setting on the View tab in Folder Options:

There are instances where turning this option off may provide a performance increase (for example, complex, multi-level nested folder structures) on the local system.  When viewing complex folder structures across the LAN/WAN, client machines may experience significant delays.  One other setting to be aware of is the NoRemoteRecursiveEvents registry setting (HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer).  When this value is set to 1 , Change Notify requests are turned off for file and folder changes occurring in mapped network share subfolders.  If a file or folder is change in the root and first folder level of the mapped share, a Change Notify event is still sent by the server.  However if a change is made at the second level (or deeper) in the structure, no Change Notify is sent.  This registry setting is set on the client machines.

Additional Resources:

- Prabhakar Shettigar

Updated Mar 16, 2019
Version 2.0

3 Comments

  • Joe_Blogson's avatar
    Joe_Blogson
    Copper Contributor

    I've been wanting the folder size feature in Windows for a long time.  That there are still people who believe such a feature would be too great a performance hit is incredible.  Mac OS has been using the feature on all its computers with no issue since the 1990s.

     

    This leads me to believe perhaps Apple has an exclusive patent on OS integrated folder size display and MSFT does not want to mention it.  In fact, I've not seen any other OS e.g. Linux, even any NAS OS with the feature.  Only Apple seems to have the feature.

     

    Third party folder sizing apps in Windows are of no use to me.  Is anyone at MSFT listening?  Why isn't viewing folder sizes the same way as does Mac OS available in Windows?

  • jmhuhn's avatar
    jmhuhn
    Copper Contributor

    Thank you for the informative explanation. 

  • JackWinston23's avatar
    JackWinston23
    Copper Contributor

    Nice tips Craig, but the tooltip size for large folders does not show correct size - try it yourself.

    I prefer to use a free tool for that: https://www.folder-sizes-explorer.com/

     

    This free tool will not only show ALL folder sizes, but has reports for largest folders and largest files. It is very easy to locate missing disk space.

    If you run it as administrator it will view also hidden files and folders likes System Volume Information etc.

     

     

    I think a newer version is available here:https://www.mindgems.com/products/Folder-Size/Folder-Size.html