Hi Dao, Checkpoint files (.chi) are identical to field files (.fld). So one would normally copy the file to a new name to prevent it from being overwritten (i.e. cp -r my_file.chk my_file.rst) then specify the .rst file in the restart section. Best, Spencer Sent from my iPhone On 25 Jul 2025, at 12:45, dxz324@student.bham.ac.uk wrote:  This email from dxz324@student.bham.ac.uk originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Dear Nektar++ Development Team, I hope you are doing well. I am currently running the APE solver of Nektar++ on the ARCHER2 supercomputing platform. I have already enabled checkpointing and successfully generated .chk files during my simulation runs. However, I could not find detailed instructions in the user guide on how to restart the solver from these checkpoint files automatically, once the allocated job time expires. Could you please advise on the correct way to configure the solver (e.g., input files or command-line options) so that it restarts from a given checkpoint file rather than starting from the initial conditions? Thank you for your time and support. Best regards, Dao _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users