I’ve been busy trying to sort a new Win X64 image out and just hit yet another wall with ImageX and DISM. For some strange reason it DISM thought the image called ARG1.wim was in a remountable state even though it had been unmounted fine previously and replaced with a new version.
After seeking info from the net and failing apart from running dism /cleanup-wim which is only useful for images in a corrupt state, I tried the ye old simple trick of renaming the image to ARG12.wim and lo and behold, no issues.
Microsoft, from the bottom of my heart…. I hate you!