diff --git a/PowerEditor/src/NppIO.cpp b/PowerEditor/src/NppIO.cpp
index d21213959..69e68a7e1 100644
--- a/PowerEditor/src/NppIO.cpp
+++ b/PowerEditor/src/NppIO.cpp
@@ -833,8 +833,17 @@ bool Notepad_plus::fileSaveAs(BufferID id, bool isSaveCopy)
 	fDlg.setDefFileName(buf->getFileName());
 	
     fDlg.setExtIndex(langTypeIndex+1); // +1 for "All types"
+
+	// Disable file autodetection before opening save dialog to prevent use-after-delete bug.
+	NppParameters *pNppParam = NppParameters::getInstance();
+	ChangeDetect cdBefore = ((NppGUI &)(pNppParam->getNppGUI()))._fileAutoDetection;
+	((NppGUI &)(pNppParam->getNppGUI()))._fileAutoDetection = cdDisabled;
+
 	TCHAR *pfn = fDlg.doSaveDlg();
 
+	// Enable file autodetection again.
+	((NppGUI &)(pNppParam->getNppGUI()))._fileAutoDetection = cdBefore;
+
 	if (pfn)
 	{
 		BufferID other = _pNonDocTab->findBufferByName(pfn);