diff --git a/de.prob.core/src/de/prob/cli/CliStarter.java b/de.prob.core/src/de/prob/cli/CliStarter.java
index 0334c426c97b6aa7da6c7aafaf78d74340fa6aa8..c9f23ecd2ab6cd30390a621f172c85395e125ff9 100644
--- a/de.prob.core/src/de/prob/cli/CliStarter.java
+++ b/de.prob.core/src/de/prob/cli/CliStarter.java
@@ -105,6 +105,7 @@ public final class CliStarter {
 
 		final ProcessBuilder pb = new ProcessBuilder();
 		pb.command(command);
+		pb.environment().put("PROB_HOME", osPath);
 		try {
 			prologProcess = pb.start();
 		} catch (IOException e) {