We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 32823

10.1.03 CORE Generator - Opening a core customization GUI results in "ERROR: sim:166 - An internal error has occurred. Closing core customization GUI."


When I attempt to create ("customize") some cores, including FIFO Generator 4.4 and Block Memory Generator 2.8, the following error occurs:

"ERROR:sim:166 - An internal error has occurred. Closing core customization GUI. An Error occurred during Customization."


This issue occurs in ISE 10.1 with service pack 3 (SP3) installed and IP Update 3 not installed. Installing the IP update should resolve the problem.

The IP Update can be downloaded from the Download Center:


In some cases, IP Update 3 does not successfully write to the $XILINX\lib\nt directory. If you have already installed IP Update 3 for ISE 10.1, use "libIp_Xst.dll" in the ISE backup install directory to replace the version in $XILINX\lib\nt.
AR# 32823
Date 11/04/2011
Status Archive
Type General Article
Page Bookmarked