General Description: When opening a Project Navigator project or changing the project preferences, the following pop-up message is issued:
"Unable to obtain a flow prefix from SFS file '<Xilinx_path>\<device_family>\data\<device _family>.sfs'."
Clicking OK or Cancel on this pop-up brings up another message box containing the project preferences. This Message box is followed with another error message: "Internal Error: Unable to load FDK set for family <device_family>".
Other related messages that may appear in conjunction with this error are:
"The value 'HDL' for the 'Top-Level Module Type' property is not valid. A default will be selected" and " This project was last saved with the project property 'Synthesis Tool' set to an invalid value of 'value>'. The project will be opened with the default value for this property."
This error will occur when the project property, 'Top-Level Module Type' is set to 'HDL' or 'Schematic' and the 'Synthesis Tool' value is blank. This can only happen if Project Navigator does not recognize any synthesis tools installed on the system. Since the Alliance Software version does not include XST synthesis, the error will most likely be encountered with the Alliance ISE software install.
To check if this is the problem, right click on the project device line in the 'Sources in Project' window and select 'Properties...'
Change the 'Top-Level Module Type' value to EDIF or NGC/NGO in the menu and to correct the problem. If the project design files include HDL or schematic files, a synthesis tool will need to be installed in order to process the design.
Related answer records: (Xilinx Answer 10150): Project Navigator, Synplicity: How do I point to the Synplify\Pro executable? (Xilinx Answer 16226): Project Navigator cannot automatically find LeonardoSpectrum version LS2002d or later (PC platform)