Problem

IntelliJ IDEA reports an error "Cannot resolve symbol"

Solutions

• Solution 1: Change or reapply the JDK

  Go to File | Project Structure | Project and select a different JDK in the SDK drop-down (download a new one if needed).

  Alternatively, remove the existing JDK, click OK to save the changes, then reopen the dialog and select the JDK from the drop-down again.

• Solution 2: Invalidate caches and restart

  1. Go to File | Invalidate Caches
  2. Check the first three boxes
  3. Click Invalidate & Restart
  4. Wait for indexing to finish, ensuring that no tasks are running in the status bar at the bottom

• Solution 3: Reset project configuration

  Try re-generating the project configuration settings:

  1. Close all open instances of the IDE
  2. Go to the project directory in your OS file explorer
  3. Delete the entire .idea folder from the project root and any *.iml files from the project root and module directories
  4. Launch the IDE, go to File | New | Project from Existing Sources, and select the project’s source (root directory or main build file)
  5. Wait for indexing to finish so that no tasks are running in the status bar at the bottom

Solution 3A: Re-import Maven or Gradle projects

If your project uses a Maven or Gradle build system:

1. Close all instances of IntelliJ IDEA
2. Clear the application cache by renaming or removing the entire IDE system directory
3. Re-import the project:
   • Go to File | Open
   • Navigate to the project directory
   • Double-click the root pom.xml or build.gradle(.kts) file
   • Choose Open as Project
4. Wait for indexing to finish so that no tasks are running in the status bar at the bottom

Solution 4: Clear the IDE system directory

1. Close all open instances of the IDE
2. Clear the application cache by removing the entire IDE system directory IDE system directory.

What to do if nothing helps

• Use this search link to check for similar issues reported in our bug tracker
• If nothing matches your case:
  • Submit a new report to YouTrack (see the guide on how to Create and Edit Issues)
  • Or contact support via Help | Contact Support from the main menu, and describe the steps you’ve already taken