<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 6.5.6

Error message:
Invalid access to memory.

Stack trace:
(0041639D) Vcl::Comctrls::TListItem::SetImage
(00EF78FE)
(00EF9976)
(00EF6720) __ExceptionHandler
(00099A1F) ntdll.dll
(00078491) ntdll.dll.KiUserExceptionDispatcher

(00EF7F69)
(00EF949C)
(00BFA3E3) RethrowException
(00DF307F) TSynchronizeChecklistDialog::Execute
(00DF19EA) DoSynchronizeChecklistDialog
(00022D33) TCustomScpExplorerForm::DoFullSynchronizeDirectories
(00121EB8) FullSynchronize
(0012A0E2) Execute
(000033BB) wWinMain
(00EF5641) C7146_0
(0006B3A9) ntdll.dll
(0006B32A) ntdll.dll

The problem happens rarely. I cannot reproduce it.

<I ran a file sync via sftp from a remote ubuntu box to my local windows 11 box. I believe it threw immediately upon the completion of the directory size calculation. I was syncing to a Nextcloud folder I had just created, however, at this time I also had Visual Studio 2022 open, and for whatever reason, the sync client craps out until I close VS (something I been fighting to figure out, have tried Owncloud as well but the sync errors were far worse).

So I'm going to toss you my best guess on this here - I'm thinking the halt occurred because of 3~ish circumstances lining up:

1). Using the Virtual File System feature with the Nextcloud sync client.
2). The Sync client was in an errored state at the time (because having VS2022 open, ugh).
3). I had created a new folder within the Nextcloud sync directory, just prior to attempting the sync operation, I'm thinking that even though I created it locally, it didn't actually create it on my local file system? Perhaps it creates it just a new virtual folder? It only had showed that little white cloud icon and not like a checkmark or green-circle-checkmark for when you want to keep data on the local machine at all times.

Hope this helps in some way, I will also see if its a repeatable issue as soon as I get a free moment again.

WinSCP 6.3.3

Error message:
Invalid access to memory.

Stack trace:
(00447F18) Vcl::Comctrls::TListItem::SetImage
(00E2235E) C6610_3
(00E243C6) ____ExceptionHandler
(00E21180) __ExceptionHandler
(0009891F) ntdll.dll
(00077E81) ntdll.dll.KiUserExceptionDispatcher

(00E229C9) C6610_3
(00E23EFC) _ThrowExceptionLDTC
(00B2D51F) RethrowException
(00D199B3) TSynchronizeChecklistDialog::Execute
(00D18A68) DoSynchronizeChecklistDialog
(000220FB) TCustomScpExplorerForm::DoFullSynchronizeDirectories
(001140AC) FullSynchronize
(0011BF8F) Execute
(000031E3) wWinMain
(00E200C1) __wstartup
(0006AE79) ntdll.dll
(0006ADFA) ntdll.dll

The problem happens rarely. I cannot reproduce it.