Thanks for your report.

This bug should be fixed in the latest version of WinSCP:
https://winscp.net/tracker/1915

I just right clicked after synchronising my local folder with my remote folder. This keeps happening even if i switch off the application. Have not tried after restart pc.

WinSCP 5.17.8

Error message:
Invalid access to memory.substring(69432)

Stack trace:
(00F78953) C3651_0
(00F89E6E) C5296_0
(00F8BED6) ____ExceptionHandler
(00F88C90) __ExceptionHandler
(000861AF) [772171

Status: all_insignificant

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.