# MCIP shows illegal instruction error
**URL:** https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902
**Category:** MCIP
**Created:** [July 9, 2025, 6:10pm UTC](https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902 "2025-07-09T18:10:25Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@ganghan2000](https://forum.cmascenter.org/u/ganghan2000)
#### Post date: [July 9, 2025, 6:10pm UTC](https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902/1 "2025-07-09T18:10:25Z")
Hello,
I’m trying to run mcip via run\_mcip script, but it shows this error.
```auto
This program uses the EPA-AREAL/MCNC-EnvPgms/BAMS Models-3
I/O Applications Programming Interface, [I/O API] which is
built on top of the netCDF I/O library (Copyright 1993, 1996
University Corporation for Atmospheric Research/Unidata
Program) and the PVM parallel-programming library (from
Oak Ridge National Laboratory).
Copyright (C) 1992-2002 MCNC,
(C) 1992-2018 Carlie J. Coats, Jr.,
(C) 2003-2012 Baron Advanced Meteorological Systems, LLC, and
(C) 2014-2020 UNC Institute for the Environment.
Released under the GNU LGPL License, version 2.1. See URL
https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
for conditions of use.
ioapi-3.2: $Id: init3.F90 185 2020-08-28 16:49:45Z coats $
Version with PARMS3.EXT/PARAMETER::MXVARS3= 2048
netCDF version 4.9.3 of May 27 2025 15:10:33 $
Missing environment variable EXECUTION_ID
forrtl: severe (168): Program Exception - illegal instruction
Image PC Routine Line Source
libc.so.6 000014A10943E730 Unknown Unknown Unknown
mcip.exe 0000000000553E95 init3 266 init3.F90
mcip.exe 00000000004A4309 init_io 44 init_io.f90
mcip.exe 000000000040EC6E mcip 19 mcip.f90
mcip.exe 000000000040EC1D Unknown Unknown Unknown
libc.so.6 000014A1094295D0 Unknown Unknown Unknown
libc.so.6 000014A109429680 __libc_start_main Unknown Unknown
mcip.exe 000000000040EB35 Unknown Unknown Unknown
```
My compiling environment is based on intel oneAPI version 2025.1.0, and IOAPI is version 3.2, compiled by same intel compiler (ifx).
At least compiling process has been done without any error, and main CMAQ runs smoothly without illegal instruction errors, but I’m not sure why this error happens.
I also read about troubleshooting page ([I/O API Troubleshooting](https://cjcoats.github.io/ioapi/ERRORS.html#inst)), but it is still uncertain that all of the programs are compiled with intel oneAPI.
Would you help me to solve this problem?
Thank you.
Ganghan
---
### Author:  [@cjcoats](https://forum.cmascenter.org/u/cjcoats)
#### Post date: [July 9, 2025, 6:43pm UTC](https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902/2 "2025-07-09T18:43:47Z")
From the I/O API Troubleshooting page, paragraph 1:
> This is probably the result of compiling either the library or the model (or both) for a different processor-model than you are running it on…
You probably need to force the compiler to generate code for the processor you’re running on; this page gives an indication how to do so.
---
### Author:  [@ganghan2000](https://forum.cmascenter.org/u/ganghan2000)
#### Post date: [July 9, 2025, 7:11pm UTC](https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902/3 "2025-07-09T19:11:17Z")
It means I have to modify Makefile in mcip source code? Or I have to check about IOAPI?
I can see the cpu flags, but still, I’m confusing about that document.
---
### Author:  [@cjcoats](https://forum.cmascenter.org/u/cjcoats)
#### Post date: [July 9, 2025, 7:32pm UTC](https://forum.cmascenter.org/t/mcip-shows-illegal-instruction-error/5902/4 "2025-07-09T19:32:53Z")
All of these (as well as netCDF and MPI) need to be compiled for the processor you’re running on. And that probably means modifying all these _Makefile_s ;-(