diff --git a/SafeExamBrowser.Browser/BrowserApplicationInstance.cs b/SafeExamBrowser.Browser/BrowserApplicationInstance.cs
index 6d35b5b1..a3f6f088 100644
--- a/SafeExamBrowser.Browser/BrowserApplicationInstance.cs
+++ b/SafeExamBrowser.Browser/BrowserApplicationInstance.cs
@@ -233,6 +233,10 @@ namespace SafeExamBrowser.Browser
 			{
 				logger.Info($"Request for '{url}' was aborted.");
 			}
+			else if (errorCode == (int) CefErrorCode.UnknownUrlScheme)
+			{
+				logger.Info($"Request for '{url}' contains unknown URL scheme and will be handled by the OS.");
+			}
 			else
 			{
 				var title = text.Get(TextKey.Browser_LoadErrorPageTitle);
diff --git a/SafeExamBrowser.Browser/Handlers/ResourceHandler.cs b/SafeExamBrowser.Browser/Handlers/ResourceHandler.cs
index a15bdd0c..b8821be2 100644
--- a/SafeExamBrowser.Browser/Handlers/ResourceHandler.cs
+++ b/SafeExamBrowser.Browser/Handlers/ResourceHandler.cs
@@ -77,6 +77,11 @@ namespace SafeExamBrowser.Browser.Handlers
 			return base.OnBeforeResourceLoad(webBrowser, browser, frame, request, callback);
 		}
 
+		protected override bool OnProtocolExecution(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IRequest request)
+		{
+			return true;
+		}
+
 		protected override void OnResourceRedirect(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, IResponse response, ref string newUrl)
 		{
 			SearchSessionIdentifiers(response);