Topic Title

I lost all 3d doors, where did they go?

1. Assuming you're using smart entities, check you paths/folders haven't changed.
2. If you mean they were visible in the drawing area, now they'r e not, try pressing 'U' to update the display list. If the doors were on a separate layer to the walls, check the layer is on and there are entities on that layer - they could have accidentally been erased?
...there could be a number of reasons they're not showing - you'll need to provide more info about the situation.

When I'm in the 3d door manager, only the default door appears

In the Door Type Manager, make certain that Display External Types is checked.

Dave