Sketch errors when changing parameters

[cnr6070]

Hello All,

I've created a model of a freight car with two sketches and some simple extrudes based on those sketches, and in those sketches I use two parameters to control the thickness of some webs.  The sketches are both fully constrained (black). 

Whenever I now modify either parameter, one or both of the sketches will show an error, either a) compute failed/failed to solve/please revise dimension or constraints (often for a dimensional relationship that is completely independent of the modified parameters), or b) it shows every dimension that includes the modified parameter in red when I open up the sketch. 

Often the sketches showing the error will become unconstrained and it seems no matter what I do to add back in or modify the sketch, it will no longer allow itself to be fully constrained.  

Sometimes Compute All helps, as can taking small steps in changing the parameters, i.e. by .25" rather than .75".  But I usually end up not being able to get to my desired new dimensions.  At some point a line is crossed and the model becomes unusable and only edit/undo can get me back to a fully constrained point.

This is frustrating as I need to be able to use one model to create both a scale version as well as one where I can increase the web thickness to reach what works on my 3D printer. 

I've searched this forum and the web in general but can't seem to find a solution that works consistently.

The problem happens on both my Windows 10 laptop and desktop computers.

Any help is appreciated.

Quinn

[davebYYPCU]

We will need to test your data, export the file or a dummy one with the problem.

[cnr6070]

See attached model file.

While creating the sketches I would periodically check that the change in parameters worked.  I developed enough confidence in the stability of the model that I stopped checking, but when the first two major sketches were complete much to my dismay the errors started.  It's almost like adding the solid operations changed something.  FWIW, deleting the solids now, the errors remain.

I notice that depending on which parameter I change, a different set of dimensions will become unsolvable.

Appreciate your help.

[davebYYPCU]

No, this one is beyond me, sorry, don't know where to start. 

Better to pattern features than sketch elements (outside gusseting), and some recommend one sketch per feature.

[Pharmcat]

I also have this problem.  It's a simple model, a sliding dovetail lid box. When I change parameters, I get the warning triangle for the width and length.  The sketch in the timeline  is yellow, I go to edit it, try to correct it and I get more confused. I've done this model over and over, sometimes it does work, but then something else goes arwy.  I've been using Fusion 360 for 3 years and have never had this problem. Idk what to do but uninstall and doing a install. Very frustrated

Thanks for any advise

Ron