IntelliJ IDEA JDK Not Found or Invalid
Fixed in latest version Windows, macOS, Linux Updated November 13, 2026Based on 3 user reportsHow we research
Quick answer
'Project SDK is not defined' or 'Invalid JDK' means the project has no usable JDK. Point the project to a standalone JDK in Project Structure; the IDE's bundled runtime cannot develop Java apps.
Most likely fix: Select or download a JDK
How to fix it
Try these in order — the most common fix is first.
1. Select or download a JDK
- Open File | Project Structure | Project Settings | Project
- Pick a JDK from the SDK list, or choose Add JDK from disk, or Download JDK
- Click Apply
Did this fix it?2. Register a global SDK
- Open File | Project Structure | Platform Settings | SDKs
- Click Add and select the JDK home directory
Did this fix it?3. Check module SDKs
- Open Project Settings | Modules, select the module, then Dependencies
- Select Project SDK to inherit it
Did this fix it?4. Set the output path
- In Project Structure | Project set the Project compiler output folder if the compile error mentions it
Did this fix it?
Symptoms
Banner saying Project SDK is not defined, run/compile buttons greyed out, or 'Cannot start compilation: the output path is not specified'.
Why it happens
- No JDK installed
- JDK moved, upgraded or deleted
- Project opened on a new machine with a different path
- Module using a different SDK than the project
This guide also covers
- intellij jdk not found
- project sdk is not defined intellij
- intellij invalid jdk
- intellij no jdk
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