I have a spreadsheet with 2 versions of text in 1 columm

1. 1 column = firstname and initial. For example Dave C.
2. 1 column = firstname. For example Dave

DaveO kindly provided this suggestion:

=MID(D7,1,FIND(" ",D7,1)-1)
where D7 contains the name in question. This formula returns
everything before the first blank space in the entry

This works perfectly for situation number 1, but in situation 2 I get a
#VALUE! error.

How can I mask the cell to be just the first name in both scenarios?

Thanks

Ben