How Can I Speed Up IntelliJ IDEA Startup and Project Indexing?

Yes, all three make a difference, and so does antivirus scanning. The steps below follow the IntelliJ IDEA 2026.2 documentation.

1. Exclude generated folders. In the Project tool window, right-click a folder and select Mark Directory As | Excluded. Excluded folders are not indexed but stay in the project. Start with build output and any folder that a tool rewrites while the IDE is open, because those writes cause repeated re-indexing. For many folders with the same name, exclude them by name pattern.
2. Use shared indexes. IntelliJ IDEA builds them once for the JDK and the project code, then reuses them on other computers. Only the rest of the project is indexed locally. For a team on one codebase, you can generate project shared indexes and host them, so each computer downloads them instead of indexing from scratch.
3. Exclude the IDE from antivirus real-time scanning. Indexing reads every project file, and the scanner checks each read. Add the project folder, the IDE installation folder, and the IDE system directory to the exclusions, as described in How to exclude IDE folders from the security scan. On Windows, the IDE detects Windows Defender and offers to add the exclusions for you.
4. Keep the project and the IDE caches on a fast local drive, not on a network drive.
5. Raise the heap only when memory is the limit. Right-click the status bar and enable Memory Indicator. If usage stays near the maximum, go to Help | Change Memory Settings, set a higher value, and click Save and Restart. A heap that is too small makes garbage collection run often. When usage stays well below the maximum, I do not expect a larger heap to change indexing time.

If one project stays slow after these steps, Indexing in JetBrains IDE is slow or stuck on a particular step lists more causes, such as recursive symbolic links. Reporting performance problems explains which data to collect for us.