section viewport

[Jason4]

Why in my sheet layer do my section viewport disappear and replaced with an outline of a red box with a X through it?Thanks

[Jonathan Pickup]

the viewport needs updating. The solution for this is to turn on the document preference to Save Viewport cache.

But be warned, this can make your files substantially bigger

[Dieter @ DWorks]

If there is a red x through it, then it means that there are no items to see in the viewport, check your clas visibility and layer visibility.

[islandmon]

If you rename a Layer used by the VP then you win a Red X Box ...

[Guest]

also make sure the data exists on the design layer and has not been deleted.

Typically, the red X means you've created a viewport that has no data to display. While it could be that layers and classes with the data are invisible for the viewport, it could also be the data on the design layers linked to the viewport does not exist either.