You will get an error if Flash Fill cannot find the pattern. The first thing to check is that you're using Flash Fill close to the source data (e.g., in the adjacent cell). For instance, it won't work ...
The SCAN function lives in a single cell and spills the results down the column, ensuring my totals are always structurally ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results