Hello again (again ^^) Witty,
Since you were asking about the creator of a parent_folder, I’m assuming you already managed to do a restart. My other response also gave an example on how to do so.
It’s very important here that besides the parent_folder, you also adapt the parameters to instruct QE to do a restart in this case (note the parameters['ELECTRONS']['startingpot'] = 'file' line in the example I gave). We discussed having restart_mode be set to 'restart' automatically when a parent_folder is provided, but decided against it because this can cause confusing behaviour in other use cases. You can find a more elaborate discussion here:
https://github.com/aiidateam/aiida-quantumespresso/pull/902#issuecomment-1501149498
As a side note: are you using the PwBaseWorkChain? This will automatically restart when the calculation hits the walltime.
Hope that helps! 🚀
Best,
Marnik