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.)> Uninstalled program and reinstalled it. No change - crashes everytime.
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.17

Error message:
Invalid access to memory.

Stack trace:
(00019740) TCustomScpExplorerForm::DoOpenFolderOrWorkspace
(00F85D26) C5296_3
(00F87D8E) ____ExceptionHandler
(00F84B48) __ExceptionHandler
(0003EF5E) ntdll.dll.ZwWow64CallFunction64
(0003F6EA) ntdll.dll.KiUserExceptionDispatcher
(000208C8) TCustomScpExplorerForm::NeedSession
(00028238) TCustomScpExplorerForm::CMShowingChanged
(0002806E) TCustomScpExplorerForm::Dispatch
(00279905) Vcl::Controls::TWinControl::WndProc
(00233DCC) Vcl::Forms::TCustomForm::WndProc
(00E3FBB0) Vclcommon::C2992_0

(00019740) TCustomScpExplorerForm::DoOpenFolderOrWorkspace
(0003EF5E) ntdll.dll.ZwWow64CallFunction64
(0003F6EA) ntdll.dll.KiUserExceptionDispatcher
(000208C8) TCustomScpExplorerForm::NeedSession
(00028238) TCustomScpExplorerForm::CMShowingChanged
(0002806E) TCustomScpExplorerForm::Dispatch
(00279905) Vcl::Controls::TWinControl::WndProc
(00233DCC) Vcl::Forms::TCustomForm::WndProc
(00E3FBB0) Vclcommon::C2992_0

(00019740) TCustomScpExplorerForm::DoOpenFolderOrWorkspace
(00F85D26) C5296_3
(00F87D8E) ____ExceptionHandler
(00F84B48) __ExceptionHandler
(0003EF5E) ntdll.dll.ZwWow64CallFunction64
(0003F6EA) ntdll.dll.KiUserExceptionDispatcher
(000208C8) TCustomScpExplorerForm::NeedSession
(00028238) TCustomScpExplorerForm::CMShowingChanged
(0002806E) TCustomScpExplorerForm::Dispatch
(00279905) Vcl::Controls::TWinControl::WndProc
(00233DCC) Vcl::Forms::TCustomForm::WndProc
(00E3FBB0) Vclcommon::C2992_0

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.