# CMAQV5.3 ISAM Region not found

**URL:** <https://forum.cmascenter.org/t/cmaqv5-3-isam-region-not-found/1418>\
**Category:** CMAQ\
**Created:** [April 7, 2020, 7:45pm UTC](https://forum.cmascenter.org/t/cmaqv5-3-isam-region-not-found/1418 "2020-04-07T19:45:21Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![hogrefe.christian](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@hogrefe.christian](https://forum.cmascenter.org/u/hogrefe.christian)\
**Post date:** [April 9, 2020, 5:00pm UTC](https://forum.cmascenter.org/t/cmaqv5-3-isam-region-not-found/1418/5 "2020-04-09T17:00:58Z")

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Regarding my second point above, please also see [this simple test](https://forum.cmascenter.org/t/icon-bcon-output-files/1366/3) suggested by @cjcoats to verify that the CMAQ\_MASK file you generated can successfully be opened and read I/O API library functions. If this test fails, your CMAQ\_MASK file wouldn’t work with CMAQ, either.

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