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

Hello, I will describe the usage before the error.
This happens when using "keep remote directory upto date". Files were being uploaded as expected. Then the i lost my internet connection for a while. After it resumed i clicked "reconnect", WinSCP connected successfully, the connect screen closed and immediately it showed this error. This error happens often once or twice a day.

"Keep remote directory upto date" Settings i used:
Update subdirectories - checked
Synchronise on start - unchecked
Transfer Settings> Exclude directories (file mask: | Thumbs.db; dwsync.xml; prepros.cfg; _notes/)


WinSCP 5.7.5

Error message:
Invalid access to memory.

Stack trace:
(00016654)
(007E39EA)
(007E5A52)
(007E29CC)
(0003E08E) ntdll.dll
(0003DEF6) ntdll.dll.KiUserExceptionDispatcher
(00074917)
(003BF59A)
(003BE996)
(00006831) USER32.DLL.CallNextHookEx
(00006A95) USER32.DLL
(00006BE8) USER32.DLL
(00006D7F) USER32.DLL
(0003DECF) ntdll.dll.KiUserCallbackDispatcher
(0000740A) USER32.DLL
(001E057C)
(0075E592)
(000A593B)
(00079AFF)
(00019804)
(000769C6)
(0007672E)
(00075CDB)
(00076422)
(000835A2)
(0001AB1C)
(00077BC5)
(0070E4FC)
(0034021C)
(00006831) USER32.DLL.CallNextHookEx
(00006A95) USER32.DLL
(00008889) USER32.DLL
(000088EC) USER32.DLL.DispatchMessageW

(003B1A2B)
(0003E08E) ntdll.dll
(0003DEF6) ntdll.dll.KiUserExceptionDispatcher
(0034021C)
(00006831) USER32.DLL.CallNextHookEx
(00006A95) USER32.DLL
(00008889) USER32.DLL
(000088EC) USER32.DLL.DispatchMessageW

(003B1618)
(0003E08E) ntdll.dll
(0003DEF6) ntdll.dll.KiUserExceptionDispatcher
(0034021C)
(00006831) USER32.DLL.CallNextHookEx
(00006A95) USER32.DLL
(00008889) USER32.DLL
(000088EC) USER32.DLL.DispatchMessageW

Status: unknown_rel_addr