DISM captures a 17GB wim file. Yet it's only 3.7GB when mounted!???

​I volunteer at a local community center. It has an Open Computer Lab for the public. It has

• An HP Server (Server 2012 R2). It’s a domain controller supporting Folder Redirection and Roaming Profiles
• 20 PCs (Windows 10 Pro v1511) but being upgrade to v1607. No hurry to get v1703. Wait 6 months for the bugs to shake out

I use MDT 2013 and Windows Deployment Service on the Server to deploy custom OS images (.wim files) to the the PCs.

The problem: I upgraded a v1511 system to v1607. Ran DiskCheck to delete the upgrade backup files that get created. I sysprep'd the PC. Then created a wim file using DISM. The wim file is 17.4GB even after maximum compression. I mount the wim to C:\_wim\MountDir to try and see what’s using all that space. But Windows shows MountDir is only 4.7GB!! The compressed wim is over 3.5x! the size of the mounted system!

More confused when I looked at the folder Properties of MounDir (as below). I also don't understand why so much difference between Size and Size on disk

• Size is 32.4GB
• Size on disk is 4.73 GB

When I run Dism /Get-WimInfo /WimFile:"C:\_wim\install.wim" /index:1 I get as follows. What’s going on and how do I get wim size down to a more reasonable size? Can anyone help????

Code:

Deployment Image Servicing and Management tool
Version: 10.0.14393.0
 
Details for image : C:\_wim\install.wim
 
Index : 1
Name : Win10 CTC-ALL v1607
Description : <undefined>
Size : 39,334,214,041 bytes
WIM Bootable : No
Architecture : x64
Hal : acpiapic
Version : 10.0.14393
ServicePack Build : 0
ServicePack Level : 0
Edition : Professional
Installation : Client
ProductType : WinNT
ProductSuite : Terminal Server
System Root : WINDOWS
Directories : 30024
Files : 152907
Created : 4/25/2017 - 1:55:34 PM
Modified : 4/25/2017 - 1:05:59 PM
Languages :
        en-US (Default)
 
The operation completed successfully.

cereberus said:

Well then you will never update again as MS have stated they intend to release new builds every 6 months. You could of course update one day before and then delay next build for 6 months ad nauseam but then you will always be six months behind latest features.

In any case, most significant bugs are usually 3rd party driver related and should be fixed pretty promptly.

Yea, i'm planning to try upgrade the current v1607 to Creator Update if only to see if DISM no longer creates a wim file 3.5X larger then the mount! Would still like to understand what's currently happening (anyone else seen similar? have similar problem?). Can only hope same problem doesn't re-occur with the new ADK 1703 when i build next wim

ComputerGeek said:

When I run Dism /Get-WimInfo /WimFile:"C:\_wim\install.wim" /index:1 I get as follows. What’s going on and how do I get wim size down to a more reasonable size? Can anyone help????

When I run that command (well, for the .esd in my case) without the /index:1 option I find there are in fact four editions in my .esd - Pro, Home, Single Language Home and Education. Could this explain the apparent 3.5 times size? Could it be you are only mounting one of the four editions?

If you try to download the .iso from https://www.microsoft.com/en-us/soft...d/windows10ISO on a non-windows system like Linux you get diverted to a page that let's you download the .iso directly. The .iso you get this way only has two editions in its .wim, Pro and Home. You can also get to this direct download page with IE or Edge by making it pretend to be a non-windows browser, as described in this tip...
How to Download Creators Update ISO via MS w/o Media Creation Tool

Bree said:

When I run that command (well, for the .esd in my case) without the /index:1 option I find there are in fact four editions in my .esd - Pro, Home, Single Language Home and Education. Could this explain the apparent 3.5 times size? Could it be you are only mounting one of the four editions?

Good question. Occurred to me too. I re-tried Dism /Get-WinInfo command using indices 2 through 9 and they all returned an error. It was worth testing out but thought there should only have a one index as the wim was created by syspreping and then capturing the disk which is a single edition install.


Re: The snapshot of MountDir folder Properties in post #1
I can't understand how/why there can be a 27.6GB difference between Size and Size on Disk and the reason might the result of the problem.

btw.. i originally tried a clean install of v1607. I don't remember the wim size but that build gave me a different problem. As the first person logging in after the wim was deployed was met with snapshot below. Didn't know if it something to do with using roaming profiles

Was sooo happy that problem didn't occur with a v1511 upgrade to v1607 but then i saw the very large wim file that was being created.