An error similar to the following occurs when I open a design that includes encrypted RTL source files in the PlanAhead tool and loads the RTL view:
Release 14.1 - Xilinx License Manager (xlicmgr) P.15xf (nt64)
Copyright (c) 1995-2011 Xilinx, Inc. All rights reserved.
ERROR:coreutil - ios failure
ERROR:sim:928 - Could not open destination 'my_encrypted_HDL.vhd' for writing.
WARNING: [Netlist-8] Can not read encrypted file 'C:\proj\Project_1.srcs\sources_1\imports\Project_1\my_encrypted_HDL.vhd' because xlicmgr command failed; please check the xlicmgr messages at the terminal
The design loads and implements fine.
This appears to be a buffer size issue with the PlanAhead tool dealing with the encrypted source files. The error message is only issued if the encrypted source is around 11 kilobytes or larger.
The error message can be ignored as the PlanAhead tool simply indicates that the content of the encrypted file cannot be viewed.