I am seriously confused now.
My 505 is not responding at all to the computer. ie I cannot manage books in any way. Sony's solution was to use Digitall Editions. This works fine for new books - I suppose - but not for managing my current content.
I have even tried re-installing from the original software but to no avail.
I have tried the DEP route which worked once but failed on the next startup.
I am sure that I am doing something basic, wrongly; but I don't know what.
Any help would be appreciated.