In a situation like that, the first thing you need to do is try an export to.idml (Remove minor corruption by exporting).
How often do you Save As, rather than just Save? Regular saves keep all the change data for the undo command, but it becomes inaccessible useless bloat when you close the file and increases the chance for corruption. Save As removes the change data. I make a habit of doing a Save As to a new version name every time I start an editing session or at each major change point during editing. Not only does it give me a ready backup chain in case something goes wrong (so I can rebuild from a nexisting file instead of starting over), but it also allows me to go back to any of those change points and pursue a new direction easily.
Good tip from Peter. I would also try zapping your InDesign preferences. Deleting your InDesign preferences can also fix some odd issues. To delete the InDesign Preferences hold down shift+option+command+control on Mac or shift+ctrl+alt on WIndows while starting up InDesign.
Also, sounds like a big file. There may be an image corrupted which you recently placed (and hopefully you are placing and not copying and pasting or dragging and dropping from other documents, for that can cause file corruption as well). I would reccomend manually breaking the links with the images by moving the file to anotehr location and try to open from there.
If this does not help, let me know.