The View RTL Schematic process is selected and nothing happens. Other Project Navigator processes and options cannot be selected.
The RTL Schematic Viewer can hang if the design contains a symbol with a name matching a Xilinx symbol but pins that do not match.
There is a step in the schematic generation where the symbols to be drawn are searched for in the symbol library. When a symbol is found, the symbol is tested for matching pins. If the test fails, a new symbol should be created. However, in this case, the symbol is not created and the tools look in the symbol library again and return the same symbol. The test for matching pins fails and repeats over and over again without first checking if the symbol has already been tested previously. This process stays in an infinite loop causing the hang.
This problem has been fixed in the latest 10.1 Service Pack available at:
The first service pack containing the fix is 10.1 Service Pack 3.