I have had an issue where I was no longer able to update my deployment share to update my boot images. If I installed MDT on another computer and connected to the share, I could then do the update, so the problem is not with the share itself but with the computer doing the updating.
I had tried uninstalling WAIK and then reinstalling it, but that did not help. I did some googling and did not come up with anything either… I was suspecting that some temp files were a problem, so I started poking around. When I looked in Users\username\AppData\Local\Temp I found some directories named MDTUpdate.XXX that were rather large.
For some reason I could not delete these files. I finally had to boot to a live CD to delete the files. Once I deleted these files, I could update my Deployment Share again.