Vnav disconnects in cruise flight when different approach selected

[brucek 38]

I've looked in the manuals and searched here, but have obviously failed to find this. This occurs 100nm from TOD, when I am picking up ATIS at KDEN from the west, and find that winds are favoring a different approach than I had assumed and programmed into the fms. When I enter a new approach VNAV disconnects- which I would expect as there is now a discontinuity in the LEGS page, but even when resolving the disconnect VNAV still will not connect.Perhaps I should not be programming an approach until I get either actual weather or a clearance to an approach. Has anyone found solution to this? I'm sure it's using what in effect is a real world simulation in non- rw conditions....Thanks, Bruce.

[blocks_off 5]

HiOut of interest, how are you generating / entering your flight plan? Asking as having a similar issue?ThanksCarl Beeby

[Spin737 102]

Creating a disco shouldn't cause VNAV to drop out. Many STARS have discos in them for vectors. Try this: select a new approach, but before you execute, clean up the legs page and then execute.