# Turning off OM3 restart checks

**URL:** <https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937>\
**Category:** COSIMA\
**Tags:** help, access-om3\
**Created:** [28 August 2026 00:34 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937 "2026-08-28T00:34:22Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![adele-morrison](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/adele-morrison/32/90_2.png) [@adele-morrison](https://forum.access-hive.org.au/u/adele-morrison)\
**Post date:** [28 August 2026 00:34 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937/1 "2026-08-28T00:34:22Z")

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I made a mistake with the forcing for the last year of an OM3 run I did. So I deleted output and restart directories for that last year of the run, and am now trying to rerun that year from an earlier restart. I’m having trouble with restart checksums failing as follows:

```auto
FATAL from PE 0: MOM_restart(restore_state): Checksum of input field u 4A328D32FF160775 does not match value CA328D32FF160775 stored in ./access-om3.mo
m6.r.1979-01-01-00000_3.nc

```

I have `skip_restart_read = .true.` in `datm_in` and `drv_in`, but I must be missing some others. Any help please?

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**Author:** ![adele-morrison](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/adele-morrison/32/90_2.png) [@adele-morrison](https://forum.access-hive.org.au/u/adele-morrison)\
**Post date:** [28 August 2026 00:44 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937/2 "2026-08-28T00:44:10Z")

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Ah, maybe I fixed it. Discovered `RESTART_CHECKSUMS_REQUIRED = False` in `MOM_input` also.

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**Author:** ![ashjbarnes](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/ashjbarnes/32/205_2.png) [@ashjbarnes](https://forum.access-hive.org.au/u/ashjbarnes)\
**Post date:** [8 October 2026 21:36 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937/3 "2026-10-08T21:36:25Z")

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Thanks @adele-morrison !

After running the first instance did you have to go back and change these settings back by hand again? I’m not really sure what the `datm` and `drv` restart checks are doing

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<div class="post-metadata">

**Author:** ![adele-morrison](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/adele-morrison/32/90_2.png) [@adele-morrison](https://forum.access-hive.org.au/u/adele-morrison)\
**Post date:** [11 October 2026 02:42 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937/4 "2026-10-11T02:42:25Z")

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I just left the restart checksums off. I am changing things all the time in my runs, so seems easier. Likely not best practice though!

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**Author:** ![dougiesquire](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/dougiesquire/32/16_2.png) [@dougiesquire](https://forum.access-hive.org.au/u/dougiesquire)\
**Post date:** [15 October 2026 08:45 UTC](https://forum.access-hive.org.au/t/turning-off-om3-restart-checks/6937/5 "2026-10-15T08:45:25Z")

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Note [we’ve fixed](https://github.com/ACCESS-NRI/MOM6/pull/96) this particular restart checksum issue in MOM6, so hopefully you mostly won’t need to touch this setting with future releases of ACCESS-OM3.