Description

The Spartan-6 FPGA MCB MIG design includes a script file, ise_flow.bat, in the output 'par' directory to run the design through implementation using the command line. 

This script file is missing the -w switch in the MAP command which causes an error if the design has already run: 

ERROR:Map:168 - Output file "example_top_map.ncd" already exists. Please specify -w to overwrite. 

ERROR:Map:151 - Problem encountered parsing the command line. 

The -w switch overwrites existing files from previous runs.

Because this switch is missing, MAP will not execute.

Solution

To fix this issue, Update the ise_flow.bat parameters for MIG v3.2.

1. MIG generates the ise_flow.bat file in the output "mig_31\example_design\par" and "mig_31\user_design\par" directories. 
   Go to either of these directories.
    
2. Open ise_flow.bat and edit the file.
   You will need to go to line 12 that starts with "map". 
    
3. Insert "-w" into the line after the "-detail" comment.
    
4. Save the file, and you should be able to re-run the file.  

This issue will be resolved in the next release of MIG in ISE 11.4.