# Error in CMAQ simulation

**URL:** <https://forum.cmascenter.org/t/error-in-cmaq-simulation/5608>\
**Category:** CMAQ\
**Tags:** cmaq\
**Created:** [February 24, 2025, 5:53am UTC](https://forum.cmascenter.org/t/error-in-cmaq-simulation/5608 "2025-02-24T05:53:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Bailey](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@Bailey](https://forum.cmascenter.org/u/Bailey)\
**Post date:** [February 24, 2025, 5:53am UTC](https://forum.cmascenter.org/t/error-in-cmaq-simulation/5608/1 "2025-02-24T05:53:46Z")

</div>

Hello，all, I got some problems in runing CMAQ5.2-CCTM, could anyone help me ?  
My simulation lasted for a month, but there was an error on the last day. So I reset the script like :  
set START\_DATE = “2020-01-30”  
set END\_DATE = “2020-01-30”

Then run it again. The error message is as follows：

 ![1740376010779](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/2X/b/b584356f9bc0cad79d4bdbd5fd7519a804f6f692.png)

---

<div class="post-metadata">

**Author:** ![lizadams](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@lizadams](https://forum.cmascenter.org/u/lizadams)\
**Post date:** [February 24, 2025, 2:11pm UTC](https://forum.cmascenter.org/t/error-in-cmaq-simulation/5608/2 "2025-02-24T14:11:42Z")

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There is not enough information in this screen shot to determine what the error is. Please review the debugging instructions here: [CMAQ/DOCS/Users\_Guide/Tutorials/CMAQ\_UG\_tutorial\_debug.md at main · USEPA/CMAQ · GitHub](https://github.com/USEPA/CMAQ/blob/main/DOCS/Users_Guide/Tutorials/CMAQ_UG_tutorial_debug.md)

Use the grep command to search for the word error in both the per processor CTM\_LOG\* files and the main log file.

```auto
grep -i error CTM_LOG_* 
grep -i error cmaq_error_log_108190.txt

```

Note, that the output log file name depends on what you are using in your run script, and whether you are using the batch queue to submit your jobs.

```auto
#SBATCH -o cmaq_error_log_%j.txt

```

Once you find which per-processor log file has an error message (not all of them will have the message), you may need to use cat or another command see the messages just prior to the error message.

```auto
grep -B 10 error CTM_LOG*

```

```auto
man grep
 -B num, --before-context=num
             Print num lines of leading context before each match. See also the -A and -C options.

```

---

<div class="post-metadata">

**Author:** ![cgnolte](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.cmascenter.org/cgnolte/32/53_2.png) [@cgnolte](https://forum.cmascenter.org/u/cgnolte)\
**Post date:** [February 25, 2025, 4:33pm UTC](https://forum.cmascenter.org/t/error-in-cmaq-simulation/5608/3 "2025-02-25T16:33:10Z")

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Another thing to check is if you want to restart your run from 2020-01-30, be sure to set NEW\_START to F at the top of the loop.