Unmount error when trying to commit a WIM-file with ImageX

If you want to mount a WIM-image with ImageX, you can mount it with read-only access or with write-access.

To mount a WIM-image with read-only access, type:
imagex /mount %path_to_wim_folder%\%filename%.wim 1 %path_to_destination_folder%

For example:
imagex /mount C:\wimfiles\win7.wim 1 C:\mounted_images

Should you decide to modify the mounted directory (like adding files to C:\mounted_images), and then commit the WIM-file, the following error appears:

ImageX Tool for Windows
Copyright (C) Microsoft Corp. All rights reserved.
Version: 6.1.7600.16385

Committing: [c:\temp\mount]…

Unmount Error: Changes to the Image could not be commited.
More Info:

An attempt was made to commit an image that was mounted for read only access.
This is not valid.  To commit an image, mount it without the read only flag
set.

This error occurs because you have mounted the image with read-only access. To mount an image with write-access, you should use the following command:
imagex /mountrw %path_to_wim_folder%\%filename%.wim 1 %path_to_destination_folder%

For example:
imagex /mountrw C:\wimfiles\win7.wim 1 C:\mounted_images

Then, after you have made some modifications, enter the commit command to write back the changes to the WIM file:
imagex /commit C:\mounted_images