Invalid access to memory - _bufchain_fetch

<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 5.9.1

Error message:
Invalid access to memory.

Stack trace:
(00614151) _bufchain_fetch
(00862736) C5073_3
(0086479E) ____ExceptionHandler
(00861558) __ExceptionHandler
(00062496) ntdll.dll
(0000F13E) ntdll.dll.KiUserExceptionDispatcher
(0060DA09) _log_proxy_stderr
(00647B2A) C2501_0
(006479D6) _handle_got_event
(006FBE2F) TSecureShell::EventSelectLoop
(006FC375) TSecureShell::Idle
(0076BA67) TTerminal::Idle
(0008EA15) TTerminalManager::Idle
(00016C6F) TCustomScpExplorerForm::Idle
(0003CEDB) TNonVisualDataModule::DoIdle
(0003CE98) TNonVisualDataModule::SessionIdleTimerTimer
(00372990) System::Classes::_18201
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167CE) USER32.dll
(00016895) USER32.dll.DispatchMessageW

(00862DA1) C5073_3
(0086437B) _ReThrowException
(0008EA5A) TTerminalManager::Idle
(00016C6F) TCustomScpExplorerForm::Idle
(0003CEDB) TNonVisualDataModule::DoIdle
(0003CE98) TNonVisualDataModule::SessionIdleTimerTimer
(00372990) System::Classes::_18201
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167CE) USER32.dll
(00016895) 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.

Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<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 5.9.2

Error message:
Invalid access to memory.

Stack trace:
(00614C81) _bufchain_fetch
(00863846) C5073_3
(008658AE) ____ExceptionHandler
(00862668) __ExceptionHandler
(000624F6) ntdll.dll
(0000F13E) ntdll.dll.KiUserExceptionDispatcher
(0060E539) _log_proxy_stderr
(0064865A) C2501_0
(00648506) _handle_got_event
(006FCC33) TSecureShell::EventSelectLoop
(006FBE6B) TSecureShell::WaitForData
(006F7275) TSecureShell::Init
(006F6B4A) TSecureShell::Open
(0076D91E) TTerminal::Open
(006C6A1F) TTerminalThread::TerminalOpenEvent
(006C19F4) TSignalThread::Execute
(000987A7) Userinterface::C20_0
(00012368) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(00863EB1) C5073_3
(0086548B) _ReThrowException
(006F7383) TSecureShell::Init
(006F6B4A) TSecureShell::Open
(0076D91E) TTerminal::Open
(006C6A1F) TTerminalThread::TerminalOpenEvent
(006C19F4) TSignalThread::Execute
(000987A7) Userinterface::C20_0
(00012368) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(00863EB1) C5073_3
(0086548B) _ReThrowException
(006F741E) TSecureShell::Init
(006F6B4A) TSecureShell::Open
(0076D91E) TTerminal::Open
(006C6A1F) TTerminalThread::TerminalOpenEvent
(006C19F4) TSignalThread::Execute
(000987A7) Userinterface::C20_0
(00012368) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(00863EB1) C5073_3
(0086548B) _ReThrowException
(006F6C38) TSecureShel

The problem happens rarely. I cannot reproduce it.

Hi,
I'm having issues downloading big files from WinSCP (arounf 270,000 kb).
This is the process I'm following and all the error messages I receive (screenshots attached):

1. I connect to Win SCP.

2. I then try to download a file of 270,000kb (at this point I already tried several things, like dragging the file to the left, or clicking the download button, and I also tried to download it with Transfer Settings: binary, which was something I checked online that could make it work), but it will always eventually fail.

3. After some seconds I will get this notification (file usually downloads until 15,000 / 20,000 kb, it's always different the size of the file, but anyway it is corrupted- picture 1.

4. The 'Abort (56s)' will go to zero and it will try to reconnect.

5. It will try to reconnect several times and a couple of different error messages can appear (always related to 'invalid access to memory')- pictures 2 and 3.

6. If I just let WinSCP continue to run in the background, it will reconnect and get these kind of errors several times.

7. Eventually I will abort the session and I will get these errors:

Basically I've been trying for several days now to download this file and it will always fail, although sometimes the download can be closer to be completed.
Can you please help me with this?

Thanks,
Joana Silva Carreira




-------------------------------------------------------------------------
WinSCP 5.13

Error message:
Invalid access to memory.

Stack trace:
(00638FC1) _bufchain_fetch
(008B9FD2) C5101_3
(008BC03A) ____ExceptionHandler
(008B8DF4) __ExceptionHandler
(000851DF) ntdll.dll
(00073161) ntdll.dll.KiUserExceptionDispatcher
(006327A5) _log_proxy_stderr
(0066CF0A) C2535_0
(0066CDA6) _handle_got_event
(007363D3) TSecureShell::EventSelectLoop
(00735603) TSecureShell::WaitForData
(00730795) TSecureShell::Init
(0073006A) TSecureShell::Open
(007B3F9D) TTerminal::OpenTunnel
(007B23CA) TTerminal::Open
(007B46CF) TTerminal::Reopen
(007B6B41) TTerminal::QueryReopen
(007AD911) TRobustOperationLoop::TryReopen
(007CF0BC) TTerminal::SinkRobust
(007CEEA0) TTerminal::DoCopyToLocal
(007A48F6) TSFTPFileSystem::CopyToLocal
(007CE9CA) TTerminal::CopyToLocal
(0000E7CD) TCustomScpExplorerForm::ExecuteFileOperation
(0000F4B4) TCustomScpExplorerForm::ExecuteFileOperation
(0001E0EF) TCustomScpExplorerForm::RemoteFileControlFileOperation
(0001E44C) TCustomScpExplorerForm::RemoteFileControlDDEnd
(0041E606) Customdirview::TCustomDirView::DDDragDetect
(0067810A) TUnixDirView::DDDragDetect
(0041AA90) Customdirview::TCustomDirView::CNNotify
(00254E85) Vcl::Controls::TControl::WndProc
(002599C9) Vcl::Controls::TWinControl::WndProc
(0029D8F7) Vcl::Comctrls::TCustomListView::WndProc
(00259B2F) Vcl::Controls::_17076
(002599C9) Vcl::Controls::TWinControl::WndProc
(00259010) Vcl::Controls::TWinControl::MainWndProc
(0037ED14) System::Classes::_1820

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.

This bug has been added to the tracker:
https://winscp.net/tracker/1623

<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 5.17.3

Error message:
Cópia de arquivos para o lado remoto falhou.

Acesso inválido à memória

Rastreamento de pilha:
(00C2A5DD) _bufchain_fetch
(00F876DE) C5296_0
(00F89746) ____ExceptionHandler
(00F86500) __ExceptionHandler
(00087E3F) ntdll.dll
(000732D1) ntdll.dll.KiUserExceptionDispatcher
(00C2A61D) _bufchain_fetch_consume
(00C2A648) _bufchain_try_fetch_consume
(00BE8E4A) _ssh2_bpp_rekey_inadvisable
(00BFED99) _ssh_ppl_user_output_string_and_free
(00BCD7E6) C2603_0
(00BCD8D9) _run_toplevel_callbacks
(00D072A0) TSecureShell::EventSelectLoop
(00D041CB) TSecureShell::DispatchSendBuffer
(00D0463E) TSecureShell::Send
(00D51D75) TSFTPFileSystem::SendPacket
(00D812A2) TSFTPUploadQueue::SendPacket
(00D76EE4) TSFTPFileSystem::Source
(00DA741F) TTerminal::Source
(00DA5F6A) TTerminal::SourceRobust
(00DA5DA9) TTerminal::DoCopyToRemote
(00D73B4E) TSFTPFileSystem::CopyToRemote
(00DA4AF9) TTerminal::CopyToParallel
(00DA4C69) TTerminal::CopyParallel
(00DA57CC) TTerminal::CopyToRemote
(00CBF585) TUploadQueueItem::DoTransferExecute
(00CBE1A6) TQueueItem::Execute
(00CBD1DA) TTerminalItem::ProcessEvent
(00CBB570) TSignalThread::Execute
(000BC0F7) Userinterface::C20_0
(00015357) KERNEL32.DLL.BaseThreadInitThunk
(00066C22) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066BEF) ntdll.dll.RtlGetAppContainerNamedObjectPath

(00F87D49) C5296_0
(00F89323) _ReThrowException
(00DA5FA7) TTerminal::SourceRobust
(00DA5DA9) TTerminal::DoCopyToRemote
(00D73B4E) TSFTPFileSystem::CopyToRemote
(00DA4AF9) TTerminal::CopyToParallel
(00DA4C69) TTerminal::CopyParallel
(00DA57CC) TTerminal::CopyToRemote
(00CBF585) TUploadQueueItem::DoTransferExecute
(00CBE1A6) TQueueItem::Execute
(00CBD1DA) TTerminalItem::ProcessEvent
(00CBB570) TSignalThread::Execute
(000BC0F7) Userinterface::C20_0
(00015357) KERNEL32.DLL.BaseThreadInitThunk
(00066C22) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066BEF) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.

<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 5.17.8

Error message:
Ha ocurrido un error al intentar copiar los archivos desde la ubicación remota.

Acceso a memoria no válido

Traza de la pila:
(00C2CC31) _bufchain_fetch
(00F89E6E) C5296_0
(00F8BED6) ____ExceptionHandler
(00F88C90) __ExceptionHandler
(00087E3F) ntdll.dll
(000732D1) ntdll.dll.KiUserExceptionDispatcher
(00C2CC71) _bufchain_fetch_consume
(00C2CC9C) _bufchain_try_fetch_consume
(00BEB122) _ssh2_bpp_rekey_inadvisable
(00C013ED) _ssh_ppl_user_output_string_and_free
(00BCF7EA) C2603_0
(00BCF8DD) _run_toplevel_callbacks
(00D09790) TSecureShell::EventSelectLoop
(00D08673) TSecureShell::WaitForData
(00D05C12) TSecureShell::Receive
(00D5685A) TSFTPFileSystem::ReceivePacket
(00D57FDC) TSFTPFileSystem::ReceiveResponse
(00D823BB) TSFTPQueue::ReceiveResponse
(00D6E604) TSFTPQueue::ReceivePacket
(00D7F7D8) TSFTPFileSystem::Sink
(00DAB60D) TTerminal::Sink
(00DAA5E6) TTerminal::SinkRobust
(00DABBB3) TTerminal::SinkFile
(00D952D2) TTerminal::ProcessDirectory
(00DAAF74) TTerminal::Sink
(00DAA5E6) TTerminal::SinkRobust
(00DABBB3) TTerminal::SinkFile
(00D952D2) TTerminal::ProcessDirectory
(00DAAF74) TTerminal::Sink
(00DAA5E6) TTerminal::SinkRobust
(00DAA42C) TTerminal::DoCopyToLocal
(00D7CD92) TSFTPFileSystem::CopyToLocal
(00DA9F77) TTerminal::CopyToLocal
(0000FD70) TCustomScpExplorerForm::ExecuteCopyMoveFileOperation
(00010848) TCustomScpExplorerForm::ExecuteFileOperation
(00010A39) TCustomScpExplorerForm::ExecuteFileOperation
(00022973) TCustomScpExplorerForm::RemoteFileControlFileOperation
(00022DA9) TCustomScpExplorerForm::RemoteFileControlDDEnd
(004488CE) Customdirview::TCustomDirView::DDDragDetect
(00C3EC96) TUnixDirView::DDDragDetect
(00444AE2) Customdirview::TCustomDirView::CNNotify
(0027611D) Vcl::Controls::TControl::WndProc
(0027AC61) Vcl::Controls::TWinControl::WndProc
(002BDF3B) Vcl::Comctrls::TCustomListView::WndProc
(0027ADC7) Vcl::Controls::_17076
(0027AC61) Vcl::Controls::TWinControl::WndProc
(0027A2A8) Vcl::Controls::TWinControl::MainWndProc
(003A58C4) System::Classes::_18201
(00043519) USER32.dll
(00024047) USER32.dll
(00023BE5) USER32.dll
(0002D23D) USER32.dll
(0007328B) ntdll.dll.KiUserCallbackDispatcher
(000234BE) USER32.dll.SendMessageW
(0005A1E1) COMCTL32.DLL
(0019DBB3) COMCTL32.DLL
(0019E4B3) COMCTL32.DLL
(0008E8D0) COMCTL32.DLL
(000544A2) COMCTL32.DLL
(00043519) USER32.dll
(00024047) USER32.dll
(0002359A) USER32.dll.CallWindowProcW
(0027AD72) Vcl::Controls::TWinControl::DefaultHandler
(0044652E) Customdirview::TCustomDirView::WMLButtonDown
(0027AC61) Vcl::Controls::TWinControl::WndProc
(002BDF3B) Vcl::Comctrls::TCustomListView::WndProc
(003A58C4) System::Classes::_18201
(00043519) USER32.dll
(00024047) USER32.dll
(0002359A) USER32.dll.CallWindowProcW
(00076417) COMCTL32.DLL
(000764B6) COMCTL32.DLL
(000761CC) COMCTL32.DLL
(00043519) USER32.dll
(00024047) USER32.dll
(0002359A) USER32.dll.CallWindowProcW
%

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.

Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<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 5.17.9

Error message:
Copying files from remote side failed.

Invalid access to memory.

Stack trace:
(00C2CC95) _bufchain_fetch
(00F89F32) C5296_0
(00F8BF9A) ____ExceptionHandler
(00F88D54) __ExceptionHandler
(0008771F) ntdll.dll
(000740A1) ntdll.dll.KiUserExceptionDispatcher
(00C2CCD5) _bufchain_fetch_consume
(00C2CD00) _bufchain_try_fetch_consume
(00BEB186) _ssh2_bpp_rekey_inadvisable
(00C01451) _ssh_ppl_user_output_string_and_free
(00BCF84E) C2603_0
(00BCF941) _run_toplevel_callbacks
(00D09854) TSecureShell::EventSelectLoop
(00D08737) TSecureShell::WaitForData
(00D05CD6) TSecureShell::Receive
(00D5691E) TSFTPFileSystem::ReceivePacket
(00D580A0) TSFTPFileSystem::ReceiveResponse
(00D8247F) TSFTPQueue::ReceiveResponse
(00D6E6C8) TSFTPQueue::ReceivePacket
(00D7F89C) TSFTPFileSystem::Sink
(00DAB6D1) TTerminal::Sink
(00DAA6AA) TTerminal::SinkRobust
(00DAA4F0) TTerminal::DoCopyToLocal
(00D7CE56) TSFTPFileSystem::CopyToLocal
(00DA7048) TTerminal::CopyToParallel
(00DA7189) TTerminal::CopyParallel
(00DA9FE3) TTerminal::CopyToLocal
(00CC2329) TDownloadQueueItem::DoTransferExecute
(00CC06EE) TQueueItem::Execute
(00CBF722) TTerminalItem::ProcessEvent
(00CBDAB8) TSignalThread::Execute
(000BCFFB) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066C7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066C49) ntdll.dll.RtlGetAppContainerNamedObjectPath

(00F8A59D) C5296_0
(00F8BB77) _ReThrowException
(00DAA73C) TTerminal::SinkRobust
(00DAA4F0) TTerminal::DoCopyToLocal
(00D7CE56) TSFTPFileSystem::CopyToLocal
(00DA7048) TTerminal::CopyToParallel
(00DA7189) TTerminal::CopyParallel
(00DA9FE3) TTerminal::CopyToLocal
(00CC2329) TDownloadQueueItem::DoTransferExecute
(00CC06EE) TQueueItem::Execute
(00CBF722) TTerminalItem::ProcessEvent
(00CBDAB8) TSignalThread::Execute
(000BCFFB) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066C7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066C49) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.

<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 5.17.10

Error message:
Cópia de arquivos do lado remoto falhou

Acesso inválido à memória

Rastreamento de pilha:
(00C2CE0D) _bufchain_fetch
(00F8A13A) C5296_0
(00F8C1A2) ____ExceptionHandler
(00F88F5C) __ExceptionHandler
(0008771F) ntdll.dll
(000740A1) ntdll.dll.KiUserExceptionDispatcher
(00C2CE4D) _bufchain_fetch_consume
(00C2CE78) _bufchain_try_fetch_consume
(00BEB1A2) _ssh2_bpp_rekey_inadvisable
(00C015C9) _ssh_ppl_user_output_string_and_free
(00BCF9C6) C2603_0
(00BCFAB9) _run_toplevel_callbacks
(00D099CC) TSecureShell::EventSelectLoop
(00D088AF) TSecureShell::WaitForData
(00D05E4E) TSecureShell::Receive
(00D56B36) TSFTPFileSystem::ReceivePacket
(00D582B8) TSFTPFileSystem::ReceiveResponse
(00D82697) TSFTPQueue::ReceiveResponse
(00D6E8E0) TSFTPQueue::ReceivePacket
(00D7FAB4) TSFTPFileSystem::Sink
(00DAB8E9) TTerminal::Sink
(00DAA8C2) TTerminal::SinkRobust
(00DAA708) TTerminal::DoCopyToLocal
(00D7D06E) TSFTPFileSystem::CopyToLocal
(00DA7260) TTerminal::CopyToParallel
(00DA73A1) TTerminal::CopyParallel
(00DAA1FB) TTerminal::CopyToLocal
(00CC24A1) TDownloadQueueItem::DoTransferExecute
(00CC0866) TQueueItem::Execute
(00CBF89A) TTerminalItem::ProcessEvent
(00CBDC30) TSignalThread::Execute
(000BCFFF) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066C7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066C49) ntdll.dll.RtlGetAppContainerNamedObjectPath

(00F8A7A5) C5296_0
(00F8BD7F) _ReThrowException
(00DAA954) TTerminal::SinkRobust
(00DAA708) TTerminal::DoCopyToLocal
(00D7D06E) TSFTPFileSystem::CopyToLocal
(00DA7260) TTerminal::CopyToParallel
(00DA73A1) TTerminal::CopyParallel
(00DAA1FB) TTerminal::CopyToLocal
(00CC24A1) TDownloadQueueItem::DoTransferExecute
(00CC0866) TQueueItem::Execute
(00CBF89A) TTerminalItem::ProcessEvent
(00CBDC30) TSignalThread::Execute
(000BCFFF) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066C7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066C49) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.

<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 5.17.10

Error message:
Invalid access to memory.

Stack trace:
(00C2CE0D) _bufchain_fetch
(00F8A13A) C5296_0
(00F8C1A2) ____ExceptionHandler
(00F88F5C) __ExceptionHandler
(0008776F) ntdll.dll
(00073E91) ntdll.dll.KiUserExceptionDispatcher
(00C2CE4D) _bufchain_fetch_consume
(00C2CE78) _bufchain_try_fetch_consume
(00BEB1A2) _ssh2_bpp_rekey_inadvisable
(00C015C9) _ssh_ppl_user_output_string_and_free
(00BCF9C6) C2603_0
(00BCFAB9) _run_toplevel_callbacks
(00D099CC) TSecureShell::EventSelectLoop
(00D08441) TSecureShell::Close
(00D082A7) TSecureShell::SetActive
(00D8CD29) TTerminal::CloseTunnel
(00D8CE11) TTerminal::Closed
(00D0839F) TSecureShell::Discard
(00C31417) _sk_newlistener
(00BE4118) _ssh_conn_processed_data
(00BE4A24) _ssh_throttle_conn
(00D082C5) TSecureShell::FreeBackend
(00D52CF3) TSFTPFileSystem::Close
(00D079EE) TSecureShell::FatalError
(00D089EB) TSecureShell::WaitForData
(00D05E4E) TSecureShell::Receive
(00D56F30) TSFTPFileSystem::ReceivePacket
(00D582B8) TSFTPFileSystem::ReceiveResponse
(00D82697) TSFTPQueue::ReceiveResponse
(00D6E8E0) TSFTPQueue::ReceivePacket
(00D7FAB4) TSFTPFileSystem::Sink
(00DAB8E9) TTerminal::Sink
(00DAA8C2) TTerminal::SinkRobust
(00DAA708) TTerminal::DoCopyToLocal
(00D7D06E) TSFTPFileSystem::CopyToLocal
(00DAA253) TTerminal::CopyToLocal
(0000FD70) TCustomScpExplorerForm::ExecuteCopyMoveFileOperation
(00010848) TCustomScpExplorerForm::ExecuteFileOperation
(00010A39) TCustomScpExplorerForm::ExecuteFileOperation
(00022973) TCustomScpExplorerForm::RemoteFileControlFileOperation
(00022DA9) TCustomScpExplorerForm::RemoteFileControlDDEnd
(00448982) Customdirview::TCustomDirView::DDDragDetect
(00C3EE72) TUnixDirView::DDDragDetect
(00444B96) Customdirview::TCustomDirView::CNNotify
(002761D1) Vcl::Controls::TControl::WndProc
(0027AD15) Vcl::Controls::TWinControl::WndProc
(002BDFEF) Vcl::Comctrls::TCustomListView::WndProc
(0027AE7B) Vcl::Controls::_17076
(0027AD15) Vcl::Controls::TWinControl::WndProc
(0027A35C) Vcl::Controls::TWinControl::MainWndProc
(003A5978) System::Classes::_18201
(0003DEB9) USER32.dll
(00034E75) USER32.dll
(00034A75) USER32.dll
(0003863D) USER32.dll
(00073E4B) ntdll.dll.KiUserCallbackDispatcher
(0003289A) USER32.dll.SendMessageW
(00068881) COMCTL32.DLL
(0019EF20) COMCTL32.DLL
(000A3C35) COMCTL32.DLL
(000648A2) COMCTL32.DLL
(0003DEB9) USER32.dll
(00034E75) USER32.dll
(00034552) USER32.dll
(000326F6) USER32.dll.CallWindowProcW
(0027AE26) Vcl::Controls::TWinControl::DefaultHandler
(004465E2) Customdirview::TCustomDirView::WMLButtonDown
(0027AD15) Vcl::Controls::TWinControl::WndProc
(002BDFEF) Vcl::Comctrls::TCustomListView::WndProc
(003A5978) System::Classes::_18201
(0003DEB9) USER32.dll
(00034E75) USER32.dll
(00034552) USER32.dll
(000326F6) USER32.dll.CallWindowProcW
(00079E57) COMCTL32.DLL
(00079EF6) COMCTL32.DLL
(00079CAC) COMCTL32.DLL
(0003DEB9) USER32.dll
(00034E75) USER32.dll
(00034552)

The problem happens rarely. I cannot reproduce it.

This happens whenever I start a second upload in parallel.

Never had this issue with an older version (not sure with which version it started though - will try out some older versions).

WinSCP 5.19.2

Error message:
Kopieren von Dateien auf den entfernten Rechner ist fehlgeschlagen.

Unzulässiger Zugriff auf einen Speicherbereich.

Stapelverfolgung:
(00C557E9) _bufchain_fetch
(00FBC612) C5294_3
(00FBE67A) ____ExceptionHandler
(00FBB434) __ExceptionHandler
(0008788F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(00C55829) _bufchain_fetch_consume
(00C55854) _bufchain_try_fetch_consume
(00C0F73A) _ssh2_bpp_rekey_inadvisable
(00C29DFD) _ssh_ppl_default_queued_data_size
(00BF3C76) C2597_0
(00BF3D69) _run_toplevel_callbacks
(00D35974) TSecureShell::EventSelectLoop
(00D327DB) TSecureShell::DispatchSendBuffer
(00D32C4E) TSecureShell::Send
(00D832B5) TSFTPFileSystem::SendPacket
(00DB2A12) TSFTPUploadQueue::SendPacket
(00DA8542) TSFTPFileSystem::Source
(00DDAF4B) TTerminal::Source
(00DD98B8) TTerminal::SourceRobust
(00DD96E5) TTerminal::DoCopyToRemote
(00DA50B6) TSFTPFileSystem::CopyToRemote
(00DD83B9) TTerminal::CopyToParallel
(00DD8529) TTerminal::CopyParallel
(00DD910A) TTerminal::CopyToRemote
(00CEE9A1) TUploadQueueItem::DoTransferExecute
(00CED526) TQueueItem::Execute
(00CEC556) TTerminalItem::ProcessEvent
(00CEA89C) TSignalThread::Execute
(000C16E3) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066A7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066A49) ntdll.dll.RtlGetAppContainerNamedObjectPath

(00FBCC7D) C5294_3
(00FBE257) _ReThrowException
(00DD98F5) TTerminal::SourceRobust
(00DD96E5) TTerminal::DoCopyToRemote
(00DA50B6) TSFTPFileSystem::CopyToRemote
(00DD83B9) TTerminal::CopyToParallel
(00DD8529) TTerminal::CopyParallel
(00DD910A) TTerminal::CopyToRemote
(00CEE9A1) TUploadQueueItem::DoTransferExecute
(00CED526) TQueueItem::Execute
(00CEC556) TTerminalItem::ProcessEvent
(00CEA89C) TSignalThread::Execute
(000C16E3) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066A7C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066A49) ntdll.dll.RtlGetAppContainerNamedObjectPath

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.

@v5vz4fap4d: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

@v5vz4fap4d: I have added this bug to the tracker:
https://winscp.net/tracker/2028