A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
A cell containing zero length string (e.g. "") is not the same as a blank cell and that may be part of the problem. If the formula in HB2 is an IF() that passes "" as one of the possible outcomes, you should check for LEN() rather than ISBLANK(). The latter covers both blank and zero length strings. Try,
=IF(LEN(HB2),IF(OR(HF2<1,HB2>E2),"Yes","No"),"")
Used in this manner, the LEN() will resolve to a FALSE for a zero length string or a blank in HB2. Anything else will be TRUE.
There is no need to make this an array formula; a simple Enter will sufffice.