Walk Forward.

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.