Hi Jonas,
I gave it another attempt and realized I missed one step.
After I added the new column, I did not set the initial values to be numeric. In my version of JMP (16.2), there is a setting now (Initialize Data) which you can set to "constant" to add the starting numbers. Leaving this setting as "Missing/Empty" led to the error.
![MetaLizard62080_0-1708381589248.png MetaLizard62080_0-1708381589248.png](https://community.jmp.com/t5/image/serverpage/image-id/61262i9CAD0E04CFCF1E60/image-size/medium?v=v2&px=400)