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 ...
One type of electronic device to especially avoid is the microwave, which emits a strong signal in the 2.4GHz band, the same wireless band your router operates in. Be careful not to stick your router ...