Issue with mtnormalise: Non-positive tissue balance factor error

Hello MRtrix3 community,

I’m encountering an error while using the mtnormalise command in my diffusion MRI analysis pipeline. When running the command with the following parameters:

mtnormalise wmfod.mif wmfod_norm.mif gmfod.mif gmfod_norm.mif csffod.mif csffod_norm.mif -mask mask.mif

I receive the following error message:

mtnormalise: [ERROR] Non-positive tissue balance factor was computed. Balance factors: 4.9786114020087711 0 0.0055108507153780427

It seems that one of the tissue balance factors is zero or negative, causing the error. I’ve checked my input data, ensured the mask is correctly defined, and reviewed the parameters used with mtnormalise, but I’m still unable to resolve the issue.

Could someone please provide guidance on how to troubleshoot and resolve this error? Any insights or suggestions would be greatly appreciated.

Thank you in advance for your help!