# How to fix ‘engine error’ when running simulation or sweeps.

Check if your simulation has enough RAM installed to run your simulation job (FDTD simulations) as described from the article:

## Then try the following:

### Windows

1. Make sure that the MPI framework you are using as your job lauching preset is installed.
2. Otherwise If one or any of the 3 is not installed, please install manually:

## Test and try to resolve the problem

• Run the simulation by changing the job launching preset to whichever is installed:

On Windows:
When using MPICH 2 and prompted for authentication as shown here:

### Works using a different MPI framework

On Windows:

• uninstall the non-working MPI from your machine
• if this is not installed, reboot your machine and install:

### If the error persist on some projects and not to all projects.

• check your simulation and make the necessary changes
• check the user account access on the folder where the simulation file is stored
• try to store/save the simulation to a local drive and folder. i.e. your Desktop
• if you do not have enough RAM on your machine, run the simulation on a different computer or make changes to lower the RAM requirement for your project.

### If the issue persists for all projects.

• Try to perform a clean installation. Uninstall / remove the software and the MPI frameworks, the installation folders, preference.INI files from your machine. Reboot and install.
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