What is SymbolCache.noindex in DerivedData?
Quick answer
~/Library/Developer/Xcode/DerivedData/SymbolCache.noindex is a small cache Xcode creates in DerivedData, with one folder per SDK version (on our Mac, MacOSX27.0.sdk (26A425), 9.5 MB). It's safe to delete with Xcode closed.
What we observed
The folder appeared in DerivedData the first time we opened a project in Xcode 27, alongside the other shared .noindex caches. It contained one folder named after an SDK and its build.
Can I delete it?
Yes. Like every .noindex folder in DerivedData, it's a cache Xcode rebuilds:
rm -rf ~/Library/Developer/Xcode/DerivedData/SymbolCache.noindexIt's small, so it's rarely worth doing on its own. Clearing all of DerivedData includes it.
Questions
Is SymbolCache.noindex related to iOS DeviceSupport symbols?
No. DeviceSupport holds symbols copied from physical devices; this is a small cache inside DerivedData.
Will it come back?
Yes, Xcode recreates it.