Operating point object is out of date

I have a Simulink model called "Plant"and when I run the following scrpit :

plant_mdl = 'Plant'; op = operspec(plant_mdl); [op_point, op_report] = findop(plant_mdl,op);

I get the error :"The model Plant has been modified and the operating point object is out of date. Update the object by calling the function update on your operating point object."

I tried op=update(op). I made sure the model has no unsaved changes , even saved The model in other names and tried the script with different model names to avoid possible shadowing problem. It keeps complaining. Does any one know what could be the reason ?

[Walter Roberson]

When you read the model are you told there are broken library links?

[Hossein Rezazadeh]

No I don't get this message. the model can run with no problem either in Simulink or on the command line.

[Abhishek Varshney]

I also got the same error :"The model Plant has been modified and the operating point object is out of date. Update the object by calling the function update on your operating point object.", when I was trying to Linearize the model using MPC Designer.

When I linearized the model first time I didn't get this type of error but when I tried to linearize the model using the same operating point file again, I got this error. I thought I have to Trim the Model again so I created a new operating point. I noted that the states were not the same. Then I got where I was wrong. Actually the simulink file was changed, I had copied the same model and pasted below the original one and used different controller. Though MPC blocks and the plant were not changed, it is treated as Plant modified.

Maybe you might have done some changes in the model that were independent of the MPC controller and the plant connected to it, and then tried to linearize with the same operating point file. So instead of that, just try Trimming again which will create a new operating file and then linearize the model.