<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.7.7

Error message:
External exception C0000006

Трассировка стека:
(00168B80) explorerframe.dll
(0008A61F) ntdll.dll
(00077E7A) ntdll.dll.KiUserExceptionDispatcher
(000199C9) DUser.dll
(00019BAB) DUser.dll
(0001A801) DUser.dll
(00018727) DUser.dll
(0001A237) DUser.dll
(0000EB51) DUser.dll
(0000E7AC) DUser.dll
(000374F1) USER32.dll
(00015C3B) USER32.dll
(000159D2) USER32.dll.CallWindowProcW
(00098CBA) COMCTL32.DLL
(00098911) COMCTL32.DLL.DefSubclassProc
(0005A1C8) explorerframe.dll
(0005AEFA) explorerframe.dll
(00098D36) COMCTL32.DLL
(00098911) COMCTL32.DLL.DefSubclassProc
(0003015B) explorerframe.dll
(0003009A) explorerframe.dll
(00098D36) COMCTL32.DLL
(00098CA1) COMCTL32.DLL
(00098ADC) COMCTL32.DLL
(000374F1) USER32.dll
(00015C3B) USER32.dll
(0001553C) USER32.dll
(00028BF6) USER32.dll.IsDialogMessageW
(00028A0F) USER32.dll
(000287FF) USER32.dll
(000286ED) USER32.dll.DialogBoxIndirectParamAorW
(000286A6) USER32.dll.DialogBoxIndirectParamW
(000203C6)COMDLG32.DLL
(0020164F) Vcl::Dialogs::TCustomFileDialog::Execute
(001FE935) Vcl::Dialogs::_16518
(001FF5D2) Vcl::Dialogs::TOpenDialog::DoExecute
(001FF487) Vcl::Dialogs::TOpenDialog::Execute
(0007E810) BrowseForExecutable
(0074EC69) TEditorPreferencesDialog::ExternalEditorBrowseButtonClick
(0021801B) Vcl::Controls::TControl::Click
(0021C609) Vcl::Controls::TWinControl::WndProc
(00185074) Vcl::Stdctrls::TButtonControl::WndProc
(0021C76F) Vcl::Controls::_17076
(0021C609%2

The problem happens rarely. I cannot reproduce it.