If this is in an Assembly, you likely have a small Part that's a good distance away from the rest of your Assembly.  Click-and-drag a box on the apparently blank space to select anything that's out there, even if you can't see it, then hit the Delete button.  Now try Shift+C again to see if that fixed the problem.  If that doesn't work check your sketches to see if there's a stray sketch element or dimension out there.  If you have a sketch out in space, but have sketches set to Hide, Zoom to Fit will still act like the sketch is visible, and perform accordingly, unless the sketch is set to Hidden in the tree, so you might check that also.


These are only a few of the possibilities; there are others.  If the click and drag box and Delete doesn't work, try suppressing components, and any other features, and then try again to track down the problem. Something is almost certainly out there.


If it's in a Drawing you may have a small sketch element that's causing the problem.  Try the same method.  If this is a drawing view of an Assembly, with some components hidden, the drawing view outline will still encompass the whole model.  Do a Cropped View around the visible components.  That should fix it.  If you're using SW2015 or later you can use the Zoom to Sheet function instead of Shift+C (SolidWorks Help - Zoom to Sheet), which will ignore the drawing view boundary if it extends past the drawing sheet.


On a related issue, I saw a post on the forum from someone that had a feature dimension thrown way away from the model.  It turns out that the problem was caused by an infinite length construction line in the feature sketch.  When the user edited the sketch and removed the infinite length from the construction line the problem went away.  I haven't used infinite length construction lines in years so I haven't personally run into this problem, but wanted to pass it along.  By the way, it isn't necessary to fully define the endpoints of a construction line to have the sketch fully defined, as long as the line's position is fully defined.  That's why I never see a need to have them infinite length (plus it just bugs me to see them extending to the edge of my graphics area).