SAS Error "Width specified for format F is invalid."

I came across the SAS error "ERROR: Width specified for format F is invalid." As that provides absolutely no hint as to what the actual problem is, it took me forever to figure it out.

What I've determined is it's a result of importing a file using proc import. Apparently there is some variable SAS doesn't like in that file (if you know exactly why, I'm all ears).

The solution is to write a "format _all_;" statement in a data step for the file before anything else is done to it. Something like this:

proc import datafile="your file" out=mydataset replace;
run;

data mydataset;
set mydataset;
format _all_;
run;

I hope it helps!