<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
My server was choking on a brutal calculation, one that I suspect required lots memory swaps to disk. I could not even SSH into the system to kill the process. (I could connect with SSH and give my password, but it failed to obtain a channel.) Refreshing a web page did work, eventually, so the thing wasn't quite dead. In any case, I tried refreshing the directory I happened to have open in WinSCP and it didn't respond, frozen, except that periodically, every 5 seconds or so, the title bar of WinSCP would update --- I saw "400 Reading Directory ... WinSCP" then with 500, 600, 700. During this, I clicked a few times on "Remote" to explore what options I might have there. No reaction. And then I got this error and here I am.
<If relevant, consider attaching a session log file or a screenshot)>
WinSCP 6.1.1
Error message:
Invalid access to memory.
Stack trace:
(00290F37) System::SysFreeMem
(0100350E) C6083_0
(01005576) ____ExceptionHandler
(01002330) __ExceptionHandler
(0009812F) ntdll.dll
(00077D31) ntdll.dll.KiUserExceptionDispatcher
(00FF1413) ___org_free
(00FDD0FD) operator delete
(00DBBFAE) TSFTPFileSystem::ResetConnection
(00DBB101) TSFTPFileSystem::Close
(00D69786) TSecureShell::FatalError
(00D684BF) TSecureShell::TimeoutAbort
(00D6A768) TSecureShell::WaitForData
(00D67AC2) TSecureShell::Receive
(00DBFD3E) TSFTPFileSystem::ReceivePacket
(00DC12E8) TSFTPFileSystem::ReceiveResponse
(00DD1584) TSFTPFileSystem::ReadDirectory
(00E00F3C) TTerminal::CustomReadDirectory
(00E002A5) TTerminal::ReadDirectory
(00DFF694) TTerminal::ReloadDirectory
(00C9126B) TUnixDirView::ReloadDirectory
(0002FEE0) TCustomScpExplorerForm::ReloadDirectory
(0004E9EA) TNonVisualDataModule::ExplorerActionsExecute
(00262B98) System::Actions::TContainedActionList::ExecuteAction
(003467AD) Vcl::Actnlist::TCustomAction::Execute
(00214D98) System::Classes::_18201
(00031E01) USER32.dll
(00022BE1) USER32.dll
(000214A0) USER32.dll
(00020FEB) USER32.dll.DispatchMessageW
The problem happens rarely. I cannot reproduce it.