In MWSWAT versions 1.5 and 1.6 there is an error in the crop table of the project database that causes an error in the .mgt files read by SWAT if landuses from the Global Landuse Maps available from the WaterBase web site are used.
In the TxtInOut folder of your project open the file input.std with, for example, Notepad. Scroll down to find the table headed HRU CN Input Summary Table and you will see in the column headed LULC the four-letter landuse codes for each HRU. They should match the corresponding values found in the headings of, for example, .mgt input files. If, for example, 000010001.mgt says the landuse is SHRB but the LULC value in the first line of the table is COFF then the error has affected your SWAT run.
If your run is affected the first thing you might want to do is to save your current Default SWAT run. To do this run MWSWAT, go straight to step 3 "SWAT Setup and Run", and use the Save run button to copy the Default scenario.
There are various answers depending how much you are able to change what you have done.
Note: If you do number 1 do not do 2 on the same project's Default scenario. Once either 1 or 2 is done on a project's Default scenario the same version of MWSWAT, or the latest version 1.7, can be safely used again on the project.This is the minimal solution that you might use if you have made some edits to your input files and do not want to rerun MWSWAT. It is also the solution to use if you need to fix and rerun SWAT on a saved scenario, i.e. not Default.
In C:\Program Files\MapWindow\Plugins\MWSWAT\Databases you will find a file cropold.dat. We will use this to replace the crop.dat file in the TxtInOut folder. Copy cropold.dat to your TxtInOut folder, delete the file crop.dat in that folder and rename cropold.dat to crop.dat in that folder.
If the TxtInOut folder is in your Default scenario then you can rerun SWAT using MWSWAT. If it is in some saved scenario, copy swat2005.exe from C:\Program Files\MapWindow\Plugins\MWSWAT to the TxtInOut folder and run it there just by double-clicking on it.
This solution rewrites only the .mgt files in your Default scenario. Close MapWindow if it is running. Find the project database (.mdb file) in the project folder and open it with Access. Delete the table crop. This will cause MWSWAT to use instead the crop table in the SWAT reference database, which does not have the error. Restart MapWindow and run MWSWAT: you can go straight to step 3 "SWAT Setup and Run" and write at least the .mgt files: select Write mgt files and click the Write files button. Then run SWAT.
If you also delete the crop table from C:\Program Files\MapWindow\Plugins\MWSWAT\mwswat.mdb then you can continue to safely use your current version of MWSWAT on new projects. This is the database that is copied to make a new project database.
If you don't mind using a new version of MWSWAT then this is the best solution for future projects as it removes the error permanently. Version 1.7 is available from the WaterBase web site.