# Cannot find mppncombine after compiling ACCESS-OM2-wombatlite

**URL:** <https://forum.access-hive.org.au/t/cannot-find-mppncombine-after-compiling-access-om2-wombatlite/5477>\
**Category:** spack\
**Tags:** spack, help, access-om2, payu, wombat\
**Created:** [30 October 2025 05:55 UTC](https://forum.access-hive.org.au/t/cannot-find-mppncombine-after-compiling-access-om2-wombatlite/5477 "2025-10-30T05:55:03Z")\
**Posts on this page:** 1\
**Showing post:** 12

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**Author:** ![anton](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/anton/32/1836_2.png) [@anton](https://forum.access-hive.org.au/u/anton)\
**Post date:** [7 November 2025 04:28 UTC](https://forum.access-hive.org.au/t/cannot-find-mppncombine-after-compiling-access-om2-wombatlite/5477/12 "2025-11-07T04:28:43Z")

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When @raslekar ran this, there was an error saying `-z` was not found in the input files. In the end, we needed to set the collate flags through the payu config as well.

In config.yaml, under the `collate:` section, we needed to set:

```yaml
    flags: -n4 -m -r​ 

```

which removes the `-z` flag which payu includes [by default](https://github.com/payu-org/payu/blob/46fb4ac890cee6b10156d853a9f4ed11322f2ed1/payu/models/fms.py#L104)

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