Hi,
I've just been going through and updating a few sites from 7.2 to 7.4. (And I am a relative drupal newbie:)
All has worked well, except on one site (which is a sub-domain test site), where I have 'lost' the ability to edit my Views.
Interestingly, I can see my Views, if i go to Structure/Blocks.
They no longer appear if I go to Stucture. My Views, or 'add Views', do not appear as a selection.
Similarly, I can still 'Configure block', but the 'Edit View' drop down option no longer diplays.