In the section that prints the SFO populations of (selected) MOs you may occasionally find, for some SFOs in some MOs, negative SFO contributions. This may seem unphysical and hence suspicious, but it is 'only' a result of the Mulliken-type analysis method that underlies the computation of the SFO contributions. See the section below that discusses the output file. Likewise for larger-than-100% contributions: don't worry too much, these numbers may be correct (mathematically, given the Mulliken population formulas).
