When I open a design that includes encrypted RTL source files in PlanAhead tool and load the RTL view, I see an error similar to the following:
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"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 PlanAhead software 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 should be ignored as PlanAhead software should simply indicate that the content of the encrypted file cannot be viewed.