Some grid lines disappear in some views

Greetings,

I just opened a 2012 project file and all of the "vertical" grid lines are not showing up in plan views. They are still there, as they are visible in elevation views.

Very puzzled.....

My guess is that the 3d element of the grid line isn't within the cut plane. Open an elevation view from a direction perpendicular to the grids that go missing and make sure that the grids cover the extent of the building (top to bottom).
My only other guess is that the category is turned off or someone use the "Hide element in view".
To find out, use the light bulb tool to turn everything on in a view where the grids don't show up. After turning on the light bulb, you should be able to see them (I think the default color for objects hidden is a reddish pink). Select one of the grid lines, right click and see if you get the option to "unhide object in view" or if you're only option is "Unhide Category". This should help figure out what method may have been used.

You also might look and see if there are some scope boxes that are limiting the visibility of a grid to certain views. select one of the grids that is only visible in an elevation view, right click for properties and look to see if that grid is associated with a scope box.

I'm having a similar issue, except its just one grid line. Its visible in my floor plans and elevations, but I can't see it in one of my details (although its there in the section view of the detail its missing in).
I've checked the "show hidden stuff" light bulb, I checked that the grid lines location is within the scope box (and that there are no other scope boxes impeding its visibility). I also tried selecting the grid from another view and "propagating views" all with no success... any other suggestions?

First I'd verify that the Detail is cut perpendicular to the grid.
Then I'd find where the 3d extents are and change those. As suggested above make sure they are sent to a scope box.
Verify that it's on a workset that's visible. Makes sure the section cut extends all the way past the grids 3d point in plan as well.
Hope that helps.