diff --git a/cli/src/main/kotlin/com/specificlanguages/mops/daemoncomms/FullClasspathDaemonLauncher.kt b/cli/src/main/kotlin/com/specificlanguages/mops/daemoncomms/FullClasspathDaemonLauncher.kt
index cb1b855..1b56b66 100644
--- a/cli/src/main/kotlin/com/specificlanguages/mops/daemoncomms/FullClasspathDaemonLauncher.kt
+++ b/cli/src/main/kotlin/com/specificlanguages/mops/daemoncomms/FullClasspathDaemonLauncher.kt
@@ -255,7 +255,9 @@ class FullClasspathDaemonLauncher(
                 mpsHome.resolve("Resources/product-info.json"),
             ).firstOrNull(Files::isRegularFile) ?: return emptyList()
             val launch = selectMpsLaunch(readMpsLaunches(descriptor), hostPlatform(osName, osArch, descriptor), descriptor)
-            return launch.bootstrapJvmArgs.map { it.replace("\$IDE_HOME", mpsHome.pathString) }
+            return launch.bootstrapJvmArgs.map {
+                it.replace("%IDE_HOME%", mpsHome.pathString).replace("\$IDE_HOME", mpsHome.pathString)
+            }
         }
 
         private fun readMpsLaunches(descriptor: Path): List<MpsLaunch> =
diff --git a/cli/src/test/kotlin/com/specificlanguages/mops/cli/FullClasspathDaemonLauncherTest.kt b/cli/src/test/kotlin/com/specificlanguages/mops/cli/FullClasspathDaemonLauncherTest.kt
index 87b329c..4e7b42e 100644
--- a/cli/src/test/kotlin/com/specificlanguages/mops/cli/FullClasspathDaemonLauncherTest.kt
+++ b/cli/src/test/kotlin/com/specificlanguages/mops/cli/FullClasspathDaemonLauncherTest.kt
@@ -63,6 +63,20 @@ class FullClasspathDaemonLauncherTest {
         assertEquals(emptyList(), FullClasspathDaemonLauncher.mpsBootstrapJvmArgs(tempDir, "Linux", "amd64"))
     }
 
+    @Test
+    fun `bootstrap classpath resolves Windows IDE home placeholder in a path with spaces`() {
+        val mpsHome = tempDir.resolve("Program Files/JetBrains/MPS 2026.2").createDirectories()
+        mpsHome.resolve("product-info.json").writeText(
+            """{"launch":[{"os":"Windows","arch":"amd64","bootClassPathJarNames":[],
+                "additionalJvmArguments":["-Xbootclasspath/a:%IDE_HOME%/lib/nio-fs.jar"]}]}""",
+        )
+
+        assertEquals(
+            listOf("-Xbootclasspath/a:$mpsHome/lib/nio-fs.jar"),
+            FullClasspathDaemonLauncher.mpsBootstrapJvmArgs(mpsHome, "Windows 11", "amd64"),
+        )
+    }
+
     @Test
     fun `exact host launch entry is preferred`() {
         val mpsHome = tempDir.resolve("mps").createDirectories()