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Troubleshooting on Windows

This article covers the most common errors Windows users may experience when starting DAISY Pipeline 2. If your issue isn’t listed here, please visit our issue tracker to report it.

ERROR: Unable to retrieve JAVA_HOME or JAVA_HOME is not valid

DAISY Pipeline 2 uses the Windows environment variable JAVA_HOME to find your Java installation folder. This error can occur if the variable is not set or pointing to an incorrect path. Please follow the steps below to set or correct your JAVA_HOME variable.

Verify Java

Before following the solution steps, first verify that you have Java installed correctly.

Windows 10: Open the search box (press Win⊞ + S, type About Java, and hit Enter. If nothing comes up, please install the latest Java version from OpenJDK.

Alternatively, open a command prompt window (press Win⊞ + R, type cmd, and hit Enter) and enter the command: java -version. This will output the version of Java installed on your computer. If the command is not recognized, please install the latest Java version from OpenJDK: choose the version “OpenJDK 11 (LTS)”, choose the VM “HotSpot”, choose your platform (“Windows x32” or “Windows x64”), click “Download JRE” and unzip the downloaded file somewhere.

Java Installation Path

You will need the path to your Java installation folder for the next steps, which can be found through File Explorer or Command Prompt.

If you got Java from http://adoptopenjdk.net, the installation path is where you unzipped it.

If you got Java from http://java.com, your Java installation path will likely resemble: C:\Program Files\Java\jre1.8.X_XXX.

You can find your Java installation path via one of these two methods:

Command Prompt (Windows 2003+)

  1. Open a command prompt window and enter the command where java (Windows 2003+).

  2. Press Ctrl + M to enter “mark” mode, highlight the path to your installation directory (e.g. jre1.8.X_XXX), and copy it.

File Explorer

Open File Explorer (Win⊞ + R, type explorer, hit Enter), and browse for your Java installation folder. It will likely be installed in either Program Files\Java or Program Files (x86)\Java on your OS drive.

Once you find your Java folder,

  1. Open to it.
  2. If there is a JRE installation folder (e.g. jre1.8.X_XXX), open it.
  3. Otherwise, open the JDK installation folder (e.g. jdk1.8.X_XXX).
  4. Copy the full path in the navigation bar at the top.


You can now set or correct your JAVA_HOME variable via one of two methods:

Command Prompt

  1. Open a Command Prompt window as administrator.
    • Windows 10: press Win⊞ + S, type cmd, then press Ctrl + Shift + Enter.
    • Or click Start, and click All Programs. Right-click Command Prompt, and then click Run as administrator.
  2. Enter the command setx JAVA_HOME -m "Path". For “Path”, paste in your Java installation path .

Control Panel

  1. Open the Control Panel (Win⊞ + R, type Control Panel, press Enter), and navigate to System and Security > System.
  2. Click on Advanced system settings link in the top left.
  3. Click on the Environment Variables button. A new window will pop up.
  4. In the bottom pane labeled System variables, click the New… button.
  5. For the variable name, enter JAVA_HOME.
  6. For the variable value, paste the path to your Java installation path.


Confirm that your JAVA_HOME variable is now set correctly.

  1. Open a Command Prompt window (Win⊞ + R, type cmd, hit Enter).
  2. Enter the command echo %JAVA_HOME%. This should output the path to your Java installation folder.
    • If it doesn’t, your JAVA_HOME variable was not set correctly. Please make sure you’re using the correct Java installation folder, or repeat the steps above.

Once you have verified that your JAVA_HOME is set correctly, DAISY Pipeline 2 should start correctly. If you experience this problem again or any others, please visit our issue tracker.