diff --git a/.vscode/settings.json b/.vscode/settings.json
index c892181..702257a 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -20,6 +20,7 @@
         "markdowndescription",
         "pasls",
         "spammy",
+        "Testcase",
         "theangryepicbanana",
         "Typecheck",
         "unregisters",
diff --git a/src/castleConfiguration.js b/src/castleConfiguration.js
index f74bfd4..78b5efb 100644
--- a/src/castleConfiguration.js
+++ b/src/castleConfiguration.js
@@ -362,7 +362,6 @@ class CastleConfiguration {
 
         // exit with clear error message when FPC compiler not found
         if (fpcExe === '') {
-
             vscode.window.showErrorMessage('FPC compiler executable not configured and not found on the PATH. Configure the FPC compiler location in the extension settings.');
             return;
         }
diff --git a/src/castlePascalLanguageServer.js b/src/castlePascalLanguageServer.js
index 5c98b9d..ad6c747 100644
--- a/src/castlePascalLanguageServer.js
+++ b/src/castlePascalLanguageServer.js
@@ -46,6 +46,14 @@ class CastlePascalLanguageServer {
         this.environmentForPascalServer['FPCTARGET'] = this._castleConfig.fpcTargetOs;
         this.environmentForPascalServer['FPCTARGETCPU'] = this._castleConfig.fpcTargetCpu;
 
+        /* pasls cannot work without FPC executable.
+           Testcase: without this line, editing settings of PP back and forth
+           from valid to invalid FPC executable location, would cause a number
+           of errors that pasls cannot be stopped because it is still starting. */
+        if (this._castleConfig.fpcExecutablePath === '') {
+            return false;
+        }
+
         /* We need to set environment variable CASTLE_ENGINE_PATH, this is
            how we pass engine path (maybe from $CASTLE_ENGINE_PATH, maybe from
            VS extension config) to pasls. */