If you try to open a model that contains syntax errors other than those marked as incorrect/incomplete equations by the Equation Editor you will not be able to view the model in the Sketch Editor. In Vensim Professional and DSS, the model will automatically be opened in the Text Editor so you can correct errors.
The other Vensim configurations do not have a Text Editor and you will be asked if you want to try to open the model anyway. If you answer yes, the equations with syntax errors will be ignored.
If a model will not open, start a new model and then look at the error history window (Windows>Error History). Scrolling to the bottom of this window will tell you why the model load failed. If you want to make changes to a .mdl file you can do so in any editor but be sure to save the results as a plain text file.
