IntelliJ IDEA Caches and Indices: The Disk Diet Every JVM Developer Eventually Needs

What actually lives in %LOCALAPPDATA%\JetBrains

Each IntelliJ version keeps its data in a pair of per-version folders: the system data under %LOCALAPPDATA%\JetBrains\IntelliJIdea2025.1 and the configuration under %APPDATA%\JetBrains\IntelliJIdea2025.1. The system side holds the heavy stuff — search indices, code caches, local history metadata, compile-server output and logs — and all of it is rebuilt from scratch when it goes missing. The config side holds your settings, plugins and license state, which is the part you never delete casually.

The structural problem is versioning: 2024.2, 2024.3, 2025.1 each get a fresh pair of folders, and nothing removes the old ones when you upgrade. After three years of point updates it is normal to find eight versions of multi-gigabyte system folders, of which exactly one is in use. Add the separate Gradle and Maven caches under %USERPROFILE%\.gradle and %USERPROFILE%\.m2 — their own enormous topic — and the JVM toolchain easily owns more disk than the operating system.

The cleanup that is safe

With the IDE closed, the order hardly matters; the only real rule is knowing which side of the system/config split you are touching. Old version folders are pure dead weight the moment the new version works, and current-version caches cost you nothing but a reindex.

• File → Invalidate Caches... — the in-IDE way; tick Clear file system cache and Local History for a full reset
• Old %LOCALAPPDATA%\JetBrains\IntelliJIdea<version> system folders — delete once the new version has worked for a few days
• system\caches and system\index of the current version — safe with the IDE closed, full reindex on next start
• system\log — months of idea.log files, free to delete
• %APPDATA%\JetBrains\<version> — config, plugins, settings; never delete unless a factory reset is the goal
• Toolbox users: %LOCALAPPDATA%\JetBrains\Toolbox\apps — remove unused IDE versions through the Toolbox UI

What to expect on the next start

After a cache wipe, IntelliJ rebuilds the indices of every project you open; on a large monorepo that means minutes of CPU and a progress bar, so do it before a deadline rather than during. Local history is lost if you cleared it — treat it as disposable-by-design, never as a backup. The payoff is proportionate: reclaiming 20 to 40 gigabytes on a well-traveled dev machine is routine, not exceptional.

To keep it from growing back, make the sweep periodic instead of heroic: fold the old-version check into the same monthly routine as the rest of your Windows cleanup — a pass with Kleaner PRO covers the JetBrains folders along with the usual temp files, and a calendar reminder does the same job for free. The JVM will always find new ways to fill a disk; the only question is whether you find out at 90 percent full or at 5 gigabytes free.

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