I was thinking that to measure a distance from a specific slope percentage, I would need to convert raster to vector and then use buffer. But the raster to vector doesn't work. Is there a better way? Basically looking to show a distance of 50 meters from a 10% slope.
produce a raster which queries your slope for 10% ( ie "Raster'' = 10)... That will produce a binary grid of 0's and 1's, The equivalent of Buffer in Raster world is Expand. if your cell size is 5 and you need 50, then Expand by 10... You can also use the Euclidean distance tool then query for the distance, but that isn't really needed.
I used Slope and then changed the classification to just have points greater and points lower than 10%. But when I use expand it says "Content
what was your cell size and how many cells did you tell it to expand by?
check the help to confirm inputs Expand—Help | ArcGIS for Desktop
Wouldn't go that far, that error came up on selecting the input.
On selecting the input means that the input is not good. Not much you can do about that except to use a backup if you have one, or recreate it from source.