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AR# 33993

11.2/11.3/11.4 XST - "ERROR:Xst:2996 - XST patch Expired"


When I use the CORE Generator tool to generate a new core or regenerate an existing core, errors similar to the following occur:

"ERROR:coreutil - Exception caught when running XST synthesis!

ERROR:coreutil - Failure to generate output products

ERROR:coreutil:576 - An error occurred while running Java. Please examine the console or coregen log file for a specific IP related error.

For more information please search the Xilinx Answers Database for this error: http://www.xilinx.com/support

ERROR:coreutil - XST has returned an error: ERROR:Xst:2996 - XST patch Expired."

How can I resolve it?


An XST file that is distributed with ISE 11.2/11.3 and 11.4 software for use with the CORE Generator tool expired on December 15, 2009.

When CORE Generator calls XST in the background to generate the core, XST exits because a time-stamp in the file has inadvertently expired.

Following is the current known list of cores that are affected by this issue:

  • DDS Compiler - dds_compiler_v4_0 (11.3)
  • Complex Multiplier - cmpy_v3_1 (11.4)
  • Fast Fourier Transform - xfft_v7_0 (11.4)
  • Divider Generator - div_gen_v3_0 (11.2)
  • Reed-Solomon Decoder - rs_decoder_v7_0 (11.2)
  • Reed-Solomon Encoder - rs_encoder_v7_0 (11.2)

To fix this issue, complete the following steps:

  1. Download the ZIP file from:
  2. Unzip the file to the $XILINX area.
    Example : c:\xilinx\11.1\ise
  3. The "ipset.txt" file will be overwritten by the unzip.

To test this patch, run the CORE Generator tool again; the core should generate without any errors.

If you have further questions, contact Xilinx Technical Support at:


AR# 33993
Date Created 12/17/2009
Last Updated 01/20/2010
Status Active
Type General Article