i have seen many of the problems arise from saved flights. it is just strange to me that some unrelated saved flights have effect on the flight u r taking. before anything, if u can delete any saved flights that u may have may actually solve the problems, if u don't have any saved flights then probably a clean download and install with the antivirus and firewall turned of may help. i had continuous dive problem and a reinstall has solved it.

Patrick, I had similar in my 757 last night, after positive climb, but before 1000 AGL flap retraction scheduled, the plane kept pitching up and up and up and finally stalled before I realized just what was happening.  I had very poor weather, and thought maybe this was the cause.  Reset back to the active, reloaded the plane, reset my FMS and all checklists and proceeded again without any trouble.  So I don't know, but worth comment that I had a similar thing there.

Haven't had the LNAV/VNAV issue the original poster mentions, but I have to wonder, what was the condition of FMS in the LEGS screen when it happened?  Unresolved Route Discontinuity will cause that sort of behavior, I think.

I just uninstalled and installed again with firewall and antivirus disabled and like to add that I installed the 4.2 version now i just cant fly were ever i take off it just cant keep in the air very strange and autopilot or no auto pilot its very unbalanced

Patrick,

This is the first I recall hearing about an AT issue like that, but some have had the AP disengage issue you mention and there is a thread specific to it here on CS forums.

Important (from my experience) to use the AP Disengage bar on the MCP, and not a soft button or the Z key, as the default FS "AP Disconnect" seems only to remove the CMD button, which is not something you can actually do in a 757, the AP Disengage bar must be pulled out.

Others have stated it's related to the 4.40 version of FSUIPC and have reported that issue goes away when reverting back to 4.30 version of FSUIPC.

Are you having the problem just with the AP, or specifically with the AP LNAV/VNAV like Alcides was originally reporting in this thread?

If so, I'd certainly check your LEGS page in the FMC and make sure there are no discontinuities, and double check against PLAN mode on the EFIS display knob and "STEP" thru the LEGS page to make sure that the route looks sane on the EHSI display.

Yup, that issue is covered in this topic