Feature update to Windows 10, version 1709 fails to install

for backup BCD. is this the steps?

1. 

 So, first let us make a folder named "BU". Either make it using File Explorer, or enter the following at a Command Prompt (Admin)...

MD  C:\BU

That makes a folder named BU into the C:\ root folder. After that, the /Export will work...

BCDEdit  /Export  "C:\BU\BCD Backup"

2. for repair and install. Can i just bring my unit to a pc shop and have them do the repair this computer option? since i am sure they have a DVD of win 10.

(1) Yes, those are the steps. You need to have a C:\BU folder, or the /Export won't work, as you saw.

(2) I guess a shop can do it. But I would backup all important user files & downloads to external media before giving it to them. Then, I would try it myself first.

i did try DISM again. same error

Microsoft Windows [Version 10.0.14393]

(c) 2016 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>DISM.exe /Online /Cleanup-image /Restorehealth

Deployment Image Servicing and Management tool

Version: 10.0.14393.0

Image Version: 10.0.14393.0

[===========================96.6%========================  ]

Error: 0x800f081f

The source files could not be found.

Use the "Source" option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see http://go.microsoft.com/fwlink/?LinkId=243077.

The DISM log file can be found at C:\WINDOWS\Logs\DISM\dism.log

C:\WINDOWS\system32>

Here is the link of dism log

https://www.dropbox.com/s/b5fkfii5bsm7lmc/dism.log?dl=0

Maybe Robert will look at that. They are difficult to figure. There isn't much human language inside.