Search Space has two options
FULL: Full will “Walk Forward” around the entire range GSB can use for a parameter.
Nearest: this will “Walk Forward” around the existing range.
See Walk Forward in GSB Guide for the Beginners
For advanced users only,
As of version 52.32, you can optionally do a walk forward to use in Enhanced Walk Forward Optimizer.
EWFO has a lot more walk forward options than GSB, Tradestation WFO or MultiCharts.
This feature however gives you much greater speed than Tradestation & MultiCharts.
It removes the need to even use Tradestation WFO or MultiCharts. at all for a walk forward.
If you want to use the path C:\Program Files (x86)\TradeStation x.y\WFO\Data
then GSB must be run with windows administrator permissions.