Thanks for your report.

<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 5.8.3

Error message:
List index out of bounds (-1)

Traza de la pila:
(0008A386) TTerminalManager::FreeTerminal
(00002275) ntdll.dll.RtlConvertUlongToLargeInteger
(0000D485) ntdll.dll.KiUserExceptionDispatcher
(00089BB7) TTerminalManager::FreeActiveTerminal
(0009838D) ShowExtendedExceptionEx
(0001C7A4) TCustomScpExplorerForm::ShowExtendedException
(0008B8ED) TTerminalManager::TerminalShowExtendedException
(007673DC) TTerminal::ShowExtendedException
(0020B0EA) Vcl::Forms::TApplication::HandleException
(0036B0F0) System::Classes::_18201
(00007731) USER32.dll
(00007811) USER32.dll
(000079C8) USER32.dll
(00007A0B) USER32.dll.DispatchMessageW

(0034E06D) System::Classes::TList::Get
(0034E06D) System::Classes::TList::Get
(00089BB7) TTerminalManager::FreeActiveTerminal
(0009838D) ShowExtendedExceptionEx
(0001C7A4) TCustomScpExplorerForm::ShowExtendedException
(0008B8ED) TTerminalManager::TerminalShowExtendedException
(007673DC) TTerminal::ShowExtendedException
(0020B0EA) Vcl::Forms::TApplication::HandleException
(0036B0F0) System::Classes::_18201
(00007731) USER32.dll
(00007811) USER32.dll
(000079C8) USER32.dll
(00007A0B) USER32.dll.DispatchMessageW

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.