Reviewed July 28, 2026 · DiskStory
How Xcode DerivedData grows—and what a safe review includes
Review a known generated-data location without widening the rule to source code, projects, or unrelated developer files.
Direct answer
DerivedData contains build products, indexes, and intermediate files that Xcode can regenerate. A safe rule matches the exact generated-data boundary, explains the cost of regeneration, and rechecks the path immediately before moving it to Trash.
Keep the boundary exact
The rule must match the known DerivedData location, not an entire Developer directory and never a source tree.
Show the regeneration cost
Removing generated data can make the next build or index slower. That consequence belongs beside the expected storage effect.
Verify the result honestly
Moving to Trash does not immediately free disk space. DiskStory rescans the original scope and records the Trash recovery location without claiming the Trash was emptied.