Start up error: missing operand at _@_ in expression "round(150 * _@_)"

I am receiving the attached error when trying to strart PolsarPro V6.0 Biomass Edition. I tried uninstalling all of the dependencies and reinstalling everything and am still getting this error.Any advice would be appreciated!

Thank you,

Hi @afpoley,
I have been facing the same problem since last 3 days as well. I’m not sure why this might be the case. I noticed that this happened after I updated the plugins for SNAP 7.0, so I suspect that might have something to do with this, but I’m not sure.
Any help on this would be pretty appreciated.


@ afpoley and @ rewanthr I am having the same problem. Did any of you solved this error. Thanks


If you are on a windows machine you can try deleting C:/Users/{USERNAME}/AppData/Roaming/PolSARpro-Bio_Version 6.0.2 released (2019.

On a MAC or linux I’m not sure where that folder is going to be located.

The AppData folder is hidden by default so you may need to play with windows settings to see it.

Additionally, that folder may contain config data which may get erased. I was working with a clean install so I did not bother trying individual files. Along the same lines since I’m not privy to what exactly is in the folder it may break the install, but it worked for me so take that as you will.


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@NBosowski Thank you for your response. I am on ubuntu and I was able to locate the hidden folder.

I deleted the hidden folder “PolSARpro-Bio_Version 6.0.2” and re-install PolSARpro again. Now everything is working fine.

Thanks again.


No problem. Just for future reference in case it happens again I did not need to reinstall PolSARpro after deleting that folder, but mileage may vary.