Error when running FDTD



I have been trying to run my 3D FDTD simulations with Lumerical, but before meshing finishes, I get an error message, and the simulation quits. The error message is shown below:


Problem signature:

Problem Event Name: APPCRASH
Application Name: fdtd-engine.exe
Application Version: 8.11.387.0
Application Timestamp: 54c68aba
Fault Module Name: fdtd-engine.exe
Fault Module Version: 8.11.387.0
Fault Module Timestamp: 54c68aba
Exception Code: c0000005
Exception Offset: 0000000000aa2ff6
OS Version: 6.0.6002.
Locale ID: 4105
Additional Information 1: 63ac
Additional Information 2: 22b0f7ee32a91cbaea92c792f05e45bf
Additional Information 3: 3ed6
Additional Information 4: baa05a30527127f5f4684dd242e85090

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I would like to know what is the cause of the problem, and how would I solve it?



It’s quite difficult to identify the cause of the problem but I noticed you are using an old version of FDTD Solutions. Can you eventually updated to the latest version (v8.16.982) and try again to see if the problem still occurs?


I will inquire with the person in charge of the FDTD licenses at our University, and try again.

Another hint that may help. I also try to run the files on Westgrid, and the log file gives an error:

FDTD Solutions Version 8.11.337 (Linux 64bit)
expires (month/day/year): 3/15/2017
current time: Thu Oct 6 13:16:40 2016
Running on host: pod23b14
All processes are communicating and ready to proceed to simulation…
Running fsp file: ./5um_modulator_SiN_wire_850nm_630nm_wg_width_modulator_diel_state.fsp
is a duplicate key.

What does it mean that it is a duplicate key?

The log file also contains the following:

The file cannot be read, it is likely corrupt.
The file cannot be read, it is likely corrupt.
There was a problem reading the file. The simulation cannot proceed.
Error: parallel error, at least one process could not read the designated file. Process number: 0 had this error



I don’t think the “duplicate key” is a problem (I’ve had that before, I think it’s just some sort of warning, if I remember correctly). The main issue I see is the other error, as it looks the processes cannot read the file.

Not sure if it is related, but it seems the version on Westgrid is slightly older than the one mentioned in the initial post. It shouldn’t be a problem as they’re both the same release, however, if you create the simulation file with the latest version, you won’t be able to run the simulation using such an old version.


I created the file using Lumerical FDTD v8.12.527 on my group’s server.

However, it appears the version on Westgrid is v8.11.337.

Do you think that could be causing the problem?

I can check with Westgrid for them to upgrade.


It could be, although I would think the error message could be different. In any case, it is safe to upgrade!



I have changed the setup file for FDTD on Westgrid such that it will use an appropriate version of FDTD.

However, it is showing the “is a duplicate key.” error, which keeps repeating itself as shown in the log file. This error comes right after the line that says the simulation is running.

The simulation is taking an indefinite amount of time, and I don’t know what the reason is.



Hi Herman,
Do you have anything in the log after the duplicate key lines? It could be useful if you could share the simulation file (before simulation so the file isn’t too big) and logs.


Hi Greg,

Please see attached the log file. The simulation file can be downloaded by this link:

I ran this on Westgrid.

HermanTemp.log (2.7 KB)


I had a look at the simulation, and started running the simulation on my computer. It seemed to work, the log doesn’t show the duplicate key lines (I’ve attached the logs).

Temp_p0.log (3.1 KB)

I’m not sure it is related, but I noted a couple of warning/errors in the script included in the “coupler” and “slab” groups. The scripts refer to objects that don’t exist (“input_bot” in “coupler” and “VO2” in “slab”). Maybe you can correct these errors or comment the lines, and see if you get the same problems. Lastly, you can try with the latest version (as I did), as it seems to work.

Also, the root of the object tree, “model” is actually an analysis group. So you don’t have to use the “coupler” group to set all the parameters, you could used the “model” object that way.


Hi Greg,

OK thanks for the suggestions. Let me try them and get back to you!


I met same situation :joy:

current time: Sun Apr 2 12:46:03 2017
Running on host: cu20
All processes are communicating and ready to proceed to simulation…
Running fsp file: /opt/lumerical/fdtd/bin/fdtd-engine-mpich2nem deep_40angle_75_zspan_150_L_7000_s_angle_-45.fsp
is a duplicate key.
is a duplicate key.
is a duplicate key.
(no more useful information)