Error reading CustomScpExplorerForm.OnClose: Invalid property value - System::Classes::TReader::ReadPropValue

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
Tried opening WinSCP after coming home from work to continue development on my website. No longer wants to open, yields the error + stack trace as given below.
Neither of the report options are valid;
- the issue is persistent
- I do not know how to produce this error from scratch. It just happened, and it doesn't go away.

<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.9.6

Error message:
Error reading CustomScpExplorerForm.OnClose: Invalid property value

Stack trace:
(003624DD) System::Classes::_17617
(00364AB4) System::Classes::TReader::ReadPropValue
(0036457A) System::Classes::TReader::ReadProperty
(00363DCD) System::Classes::TReader::ReadDataInner
(00363D80) System::Classes::TReader::ReadData
(00371971) System::Classes::TComponent::ReadState
(00208A2D) Vcl::Forms::TCustomForm::ReadState
(00364D5B) System::Classes::TReader::ReadRootComponent
(0035EC26) System::Classes::TStream::ReadComponent
(0035466B) System::Classes::_17089
(00355FBF) System::Classes::_17116
(00355F94) System::Classes::_17116
(0035604D) System::Classes::InitInheritedComponent
(00208226) Vcl::Forms::TCustomForm::TCustomForm
(00003FC6) Vcl::Forms::TForm::TForm
(000036D9) TCustomScpExplorerForm::TCustomScpExplorerForm
(0003FC82) TScpCommanderForm::TScpCommanderForm
(002131D6) Vcl::Forms::TApplication::CreateForm
(00811137) _SafeFormCreate
(000024A8) wWinMain
(008669E1) __wstartup
(0005FFD7) ntdll.dll
(0005FF9F) ntdll.dll

(0036439F) System::Classes::_17687
(003645D9) System::Classes::TReader::ReadProperty
(00363DCD) System::Classes::TReader::ReadDataInner
(00363D80) System::Classes::TReader::ReadData
(00371971) System::Classes::TComponent::ReadState
(00208A2D) Vcl::Forms::TCustomForm::ReadState
(00364D5B) System::Classes::TReader::ReadRootComponent
(0035EC26) System

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 6.3.2

Error message:
Error reading ImageList144.Top: Access violation at address 00248DB3 in module 'WinSCP.exe'. Read of address 00000000

Stack trace:
(00217DB3) System::Classes::TReader::ReadPropValue

(002178DF) System::Classes::_17687
(00217B19) System::Classes::TReader::ReadProperty
(0021730D) System::Classes::TReader::ReadDataInner
(002172EF) System::Classes::TReader::ReadData
(00224F69) System::Classes::TComponent::ReadState
(00217381) System::Classes::TReader::ReadDataInner
(002172C0) System::Classes::TReader::ReadData
(00224F69) System::Classes::TComponent::ReadState
(003C274D) Vcl::Forms::TCustomForm::ReadState
(00D05200) TProgressForm::ReadState
(00212166) System::Classes::TStream::ReadComponent
(00207BAB) System::Classes::_17089
(002094FF) System::Classes::_17116
(0020958D) System::Classes::InitInheritedComponent
(003C1F46) Vcl::Forms::TCustomForm::TCustomForm
(00005912) Vcl::Forms::TForm::TForm
(00CFEC8B) TProgressForm::TProgressForm
(0000B8F0) TCustomScpExplorerForm::CreateProgressForm
(0000BA94) TCustomScpExplorerForm::FileOperationProgress
(0005C7F2) TScpCommanderForm::FileOperationProgress
(0000BDFE) TCustomScpExplorerForm::OperationProgress
(000C4006) TTerminalManager::OperationProgress
(00B38864) TFileOperationProgressType::DoProgress
(00C67C07) TTerminal::OperationStart
(00C67B7D) TTerminal::OperationStart
(00C67D26) TTerminal::ProcessFiles
(00C6B1C6) TTerminal::CalculateFilesSize
(00C7D6D7) TTerminal::CopyToLocal
(00015D1E) TCustomScpExplorerForm::TemporarilyDownloadFiles
(00018883) TCustomScpExplorerForm::ExecutedFileReload
(00080558) TEditorManager::FileReload
(00CB6A33) TEditorForm::Reload
(00CB37FE) TEditorForm::EditorActionsExecute
(00359731) Vcl::Actnlist::TCustomAction::Execute
(00226F88) System::Classes::_18201
(00032451) USER32.dll
(000232A1) USER32.dll
(00021B60) USER32.dll
(000216AB) USER32.dll.DispatchMessageW

(00E21D6D) C6608_3
(00E23347) _ReThrowException
(00C60CBF) TTerminal::DoProgress
(00B38864) TFileOperationProgressType::DoProgress
(00C67C07) TTerminal::OperationStart
(00C67B7D) TTerminal::OperationStart
(00C67D26) TTerminal::ProcessFiles
(00C6B1C6) TTerminal::CalculateFilesSize
(00C7D6D7) TTerminal::CopyToLocal
(00015D1E) TCustomScpExplorerForm::TemporarilyDownloadFiles
(00018883) TCustomScpExplorerForm::ExecutedFileReload
(00080558) TEditorManager::FileReload
(00CB6A33) TEditorForm::Reload
(00CB37FE) TEditorForm::EditorActionsExecute
(00359731) Vcl::Actnlist::TCustomAction::Execute
(00226F88) System::Classes::_18201
(00032451) USER32.dll
(000232A1) USER32.dll
(00021B60) USER32.dll
(000216AB) USER32.dll.DispatchMessageW

(00E21D6D) C6608_3
(00E23347) _ReThrowException
(00B385D5) TFileOperationProgressType::Start
(00C67C07) TTerminal::OperationStart
(00C67B7D) TTerminal::OperationStart
(00C67D26) TTerminal::ProcessFiles
(00C6B1C6) TTerminal::CalculateFilesSize
(00C7D6D7) TTermina

The problem happens rarely. I cannot reproduce it.