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If the model stops more than once at the same timestep have a look at the listings of ALL processes to see what went wrong.
If the model stops after having written (or started to write) the restart files you always have to restart the simulation from the previous month.
Meaning if you have the line in the listing saying:
oe-00000-00000: WRITING A RESTART FILE AT TIMESTEP # ...
When the Fortran executable finishes fine, you will see the following messages at the end of the main process listing:
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