I am unable to select a search distance or measurement unit when using the Select Layer by Location tool. This defeats the purpose of selecting "within a distance".
Your units are unknown, that is why it is greyed out. what type of file is it? looks like some basemap rather than a featureclass with a known coordinate system
You are on the right track about the units. The input and selecting features are from a feature class and feature service so it should work. I am using "Model Builder" and the problem was that I tried to use a parameter for the source distance and had it set to Long instead of Linear Units. When I deleted the parameter and tried to input the distance and units manually the box was greyed out. This is unwanted behavior but it is a small thing comparatively. I "encountered a serious application error..." a few minutes later and "The error report is too large..." I agree, the number of errors is very large.
Retrieving data ...