I'm not sure you understood my question - the maximum number of error codes in any one cell, i.e. in a single cell in column A, the total number of letters which might be included.

If it helps to clarify, mdw's solution is good to 7, try putting 8 letters in to a cell in col A on sheet 1.

Depending on the maximum you might need, different solutions (I agree with mdw, probably VBA if it gets much more complicated) are appropriate.

hth