This is a follow-up question from ticket ID28300026, but unrelated enough that I felt it was suitable to create a new post.
This same Windows 8.1 machine was having troubles, so replaced the HDD and started from scratch, installing and setting up Windows 8, then upgrading to Windows 8.1 via the Windows Store.
All user data was transferred successfully to the machine from a reasonably current backup. However, originally when trying to open a document, it would only show in read-only mode. A quick permissions adjustment saw that issue resolved, however we don't seem to be able to save documents anymore (we're told we don't have the permission. Interestingly, data can be saved onto external USB devices without issue and, even more interesting, we can create a folder, move files (and sub-folders!) in the folder we can't save to into the newly created folder and can then open, save and do whatever we please without incident.
It sounds like a permissions/ ownership issue to me, but I thought I'd done it correctly (unless what I've done previously through Windows 7 isn't as effective here.
Would love to know the best course of action because I know there's a better way to resolve this that to create a whole bunch of new folders and transfer everything to those!