Easy one . . . why can't use "R1D" as a cell name

[Jeffrey Green]

I am trying to use R1D as a cell NAME in a CELL.

it doesnt start with a number
it doesnt have a space
and it is not already defined
and it isnt a cell reference.

just academic at this point . . thanks

 

[Scott Huish]

Just an educated guess, but probably because it's starting with R1, it is likely trying to interpret it as a cell reference in R1C1 format, and therefore not allowing it.
In much the same way that you can't name a cell B2 for example.