This answer record details the known issues related to the Xilinx implementation of FLEXnet licensing for the 2012 Vivado and 14.x ISE Design Suite release.
For license troubleshooting help, see (Xilinx Answer 32301).
For the Licensing Solution Center, see (Xilinx Answer 41259).
For general questions about software licensing, see the following Xilinx Licensing FAQ page.
Xilinx Licensing Site:
http://www.xilinx.com/getlicense
Known Issues in Vivado 2013.1
(Xilinx Answer 30526) - FLEXnet fails to find license when the computer default network interface is "eth1" (instead of "eth0")
(Xilinx Answer 33026) - Xilinx License Configuration Manager (XLCM) might take a long time to load the available licenses
(Xilinx Answer 33719) - XLCM shows only one available seat when a license file contains multiple entries of a feature
(Xilinx Answer 52062) - Floating IP license is not recognized in the Vivado tool if the IP license is on a different server than the Vivado license
(Xilinx Answer 52723) - XLCM does not handle paths with Simplified Chinese characters