diff --git a/src/Common/BootEncryption.cpp b/src/Common/BootEncryption.cpp
index 1fb26a9a..215b1f86 100644
--- a/src/Common/BootEncryption.cpp
+++ b/src/Common/BootEncryption.cpp
@@ -1041,7 +1041,7 @@ namespace VeraCrypt
 		FileOpen = false;
 		Elevated = false;
 
-		if (path.find(L"\\\\?\\") == 0)
+		if (path.find(L"\\\\?\\") == 0 || path.find(L"\\\\.\\") == 0)
 			effectivePath = path;
 		else
 			effectivePath = wstring (L"\\\\.\\") + path;
diff --git a/src/Format/FormatCom.cpp b/src/Format/FormatCom.cpp
index 738116b0..a78c96fb 100644
--- a/src/Format/FormatCom.cpp
+++ b/src/Format/FormatCom.cpp
@@ -92,6 +92,8 @@ public:
 
 	virtual BOOL STDMETHODCALLTYPE FormatNtfs (int driveNo, int clusterSize)
 	{
+		if (driveNo < 0 || driveNo > 25)
+			return ERROR_INVALID_PARAMETER;
 		return ::FormatNtfs (driveNo, clusterSize, TRUE);
 	}
 
@@ -134,6 +136,8 @@ public:
 
 	virtual BOOL STDMETHODCALLTYPE FormatFs (int driveNo, int clusterSize, int fsType)
 	{
+		if (driveNo < 0 || driveNo > 25)
+			return ERROR_INVALID_PARAMETER;
 		return ::FormatFs (driveNo, clusterSize, fsType, TRUE);
 	}