<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 5.15.2

Error message:
External exception C000001D

Stack trace:
(007BD540) void TSessionData::SetAlgoList<TGssLib>
(0007E19F) ntdll.dll
(0006BD81) ntdll.dll.KiUserExceptionDispatcher
(007BC600) TSessionData::SetGssLibList
(0079CFE9) TSessionData::CopyData
(0079CBCF) TSessionData::Assign
(0001DFDE) TCustomScpExplorerForm::DoSaveWorkspace
(000298C9) TCustomScpExplorerForm::FormClose
(00232933) Vcl::Forms::TCustomForm::DoClose
(00278F45) Vcl::Controls::TWinControl::WndProc
(0023340C) Vcl::Forms::TCustomForm::WndProc

The problem happens rarely. I cannot reproduce it.