Issues with resuming simulations

[Lautaro Alvear]

Hi Dedalus experts, I was trying to resume a simulation using a similar logic to that of the Internally heated convection example and i was having trouble with the append

file_handler_mode. What I do is

file_read = f"{filesnapshots}/{filesnapshots}_s{resume_index}.h5"
write, initial_timestep = solver.load_state(file_read,allow_missing=True)
if initial_timestep > max_timestep:
    initial_timestep = max_timestep
file_handler_mode = 'append'
snapshots = solver.evaluator.add_file_handler(filesnapshots, sim_dt=dt_writes*tA, max_writes=int(max_time_writes/dt_writes), mode=file_handler_mode)

the line that reads the last snapshot works fine, but in the line that I define the file handler, I get the following error

Traceback (most recent call last):
 File "/home/lalvear/CompressibleNS/Star_stability_v2.py", line 825, in <module>
   slices = solver.evaluator.add_file_handler(filesnapshots, sim_dt=dt_writes*tA, max_writes=int(max_time_writes/dt_writes), mode=file_handler_mode)
 File "/home/lalvear/miniforge3/envs/dedalus3/lib/python3.13/site-packages/dedalus/core/evaluator.py", line 74, in add_file_handler
   return self.add_handler(FileHandler(filename, self.dist, self.vars, **kw))
                           ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/home/lalvear/miniforge3/envs/dedalus3/lib/python3.13/site-packages/dedalus/core/evaluator.py", line 422, in __init__
   max_set = max(set_nums)
ValueError: max() iterable argument is empty

as I understand, Dedalus is trying to to find the last index of the data in filesnapshots, but it is not finding anything in the file. This shouldn't be the case, since when I read the file to load the state of the solver it works just fine. I would be very grateful if someone could help me with this, as this forces me to restart the whole simulation if it gets canceled for any reason.

Best regards,
Lautaro.