This page can be accessed only when there are errors or warnings. If there are no errors or warnings, then this page will be visible in the workflow, but it cannot be accessed. On this page there are two tables. The top table "Errors/Warnings Overview" lists all the errors and warnings which were encountered when reading the Excel Data File.
For every error/warning it lists the following three characteristics:
Count: the number of occurrences of this particular error/warning
Type: the type of each error: Fatal, Error, or Warning
Category: the classification of each error, which can help you in grouping errors together (e.g. for fixing)
There are three types of errors with different levels of impact:
Fatal: These are errors which must be fixed before you can save the data. This type of errors always causes infeasibility. For example if the supplier's maximum capacity is lower then the minimum capacity.
Error: These are errors which should be fixed, but this is not mandatory. However, if they are not fixed, it is likely that they will lead to issues while solving the model. For example if the warehouse inventory's minimum or maximum capacity is negative.
Warning: These are warnings which you should review. However, even if they are not prevented, you can still save the data and the solving of the model will run without issues. For example if the warehouse is not available but there is fixed cost defined for the warehouse.
These error/warning types also impact how you can save the data. In particular, you will not be able to save the data when there is a fatal error. Fatal errors mean that there is something structurally wrong which needs to be fixed firstly. And in that case you are not able to optimize the model, fatal errors should be fixed first.
Type errors can be saved by using the top button in the lower right corner. However, before you do that, you will be asked to confirm that you really want to save the data. The reason for this is that it is very well possible that you will not be able to solve the model while those errors are still present. But on the other pages the Saving button is not available.
It is good to inspect warnings, but they will most likely not lead to major issues in solving the model, and therefore, you can use the button at the bottom. This button is also available on the other pages in the workflow.
In the table above you can select a row in order to get more details on the error/warning, details which will appear in the second table. This contains a description of all the errors of this type, so that they can help you fix the errors.
In the picture below you can notice the two "Save Dataset" buttons as described above.