diff --git a/scripts/Start-EditorServices.ps1 b/scripts/Start-EditorServices.ps1
index 9f96d917d4..ce2545d0fa 100644
--- a/scripts/Start-EditorServices.ps1
+++ b/scripts/Start-EditorServices.ps1
@@ -89,6 +89,16 @@ function WriteSessionFile($sessionInfo) {
     ConvertTo-Json -InputObject $sessionInfo -Compress | Set-Content -Force -Path "$SessionDetailsPath" -ErrorAction Stop
 }
 
+if ($host.Runspace.LanguageMode -eq 'ConstrainedLanguage') {
+    WriteSessionFile @{
+        "status" = "failed"
+        "reason" = "languageMode"
+        "detail" = $host.Runspace.LanguageMode.ToString()
+    }
+
+    ExitWithError "PowerShell is configured with an unsupported LanguageMode (ConstrainedLanguage), language features are disabled."
+}
+
 # Are we running in PowerShell 5 or later?
 $isPS5orLater = $PSVersionTable.PSVersion.Major -ge 5
 
diff --git a/src/session.ts b/src/session.ts
index fad251e751..fdb9d1e48f 100644
--- a/src/session.ts
+++ b/src/session.ts
@@ -327,6 +327,10 @@ export class SessionManager {
                                 this.setSessionFailure(
                                     `PowerShell language features are only supported on PowerShell version 3 and above.  The current version is ${sessionDetails.powerShellVersion}.`)
                             }
+                            else if (sessionDetails.reason === "languageMode") {
+                                this.setSessionFailure(
+                                    `PowerShell language features are disabled due to an unsupported LanguageMode: ${sessionDetails.detail}`);
+                            }
                             else {
                                 this.setSessionFailure(`PowerShell could not be started for an unknown reason '${sessionDetails.reason}'`)
                             }
diff --git a/src/utils.ts b/src/utils.ts
index 0db0a5619b..6dcb0bbf18 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -57,6 +57,7 @@ export function getPipePath(pipeName: string) {
 export interface EditorServicesSessionDetails {
     status: string;
     reason: string;
+    detail: string;
     powerShellVersion: string;
     channel: string;
     languageServicePort: number;