<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:
Chyba přístupu do paměti.

Stack trace:
(007698CA) TMessageForm::Create
(0008A63F) ntdll.dll
(00077E9A) ntdll.dll.KiUserExceptionDispatcher
(0076AFD5) CreateMoreMessageDialog
(0009F2DA) CreateMessageDialogEx
(0009FA45) MoreMessageDialog
(0009FC40) MessageDialog
(0000CC18) TCustomScpExplorerForm::ExecuteFileOperation
(0000CFB0) TCustomScpExplorerForm::ExecuteFileOperation
(0000D037) TCustomScpExplorerForm::ExecuteFileOperationCommand
(00032184) TNonVisualDataModule::ExplorerActionsExecute
(00382614) System::Actions::TContainedActionList::ExecuteAction
(0016A155) Vcl::Actnlist::TCustomAction::Execute
(0034059C) System::Classes::_18201
(000374F1) USER32.dll
(00015C3B) USER32.dll
(0001553C) USER32.dll
(000152FB) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.