PS....

On Jun 4, 4:21 pm, joeu2004 I wrote:
3. Like RATE(), sometimes IRR() and XIRR() need help by your providing
a "guess" parameter.

Alternatively, you can change the number iterations and the step-size
for change between iterations. See the Help page for "Correct a #NUM!
error" for guidance.

This might be acceptable for simple spreadsheets -- for example, when
you are calculating only the one rate. But it might be prohibitive
for complex spreadsheets because it might slow down recalculation
significantly.

In any case, there is no assurance that changing those internal
parameters will avoid the "error" (failure to compute the rate) in
specific cases.