.aup "simpleblockfile filename" missing

I try opening an hour long radio show I’m working on (5 mins of speech to add to finish) and get all the files as silence with the usual warning about orphaned files etc, after much research I see that the problem is that the txt in the .aup file has no reference to the data files and looks like this

<simpleblockfile filename="" len="262144" min="-0.891251" max="0.714625" rms="0.095432"/>

There seems to be no mention to any of the data files between the two “” unlike in previous .aup files that I have

<simpleblockfile filename="e00017ff.au" len="244745" min="-0.477988" max="0.47621" rms="0.133488"/>

I have a gigs worth of data files in the data folder.
I do not have any temp files in AppData\Local\Audacity as did a clean with ccleaner last night, at least I think thats why there are no files there.
So my question is, is there anyway to get/fool audacity into finding those files? I know its probably a long shot!
Also why did this happen?
thanks for any advice
windows 7 audacity 2.2.2