I encountered the following error during synthesis using XST after migrating from ISE software 11.1 to 11.4.
ERROR:Xst:2843 - Required system file hdc.ini not found through XILINX environment variable. Make sure your XILINX environment variable is set properly. Error found during generation.
This error is caused by hdc.ini under $XILINX\vhdl\xst\nt not found.
To work around it:
1. Check if XILINX environment variable is set properly.
2. Check if hdc.ini exists under $XILINX\vhdl\xst\nt. If it is missing, the issue can be resolved by copying all missing files under $XILINX\vhdl\xst\nt from another machine.