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.

Portable version. While I just upgraded, this happened in prior version as well. Seems to be session-specific, meaning if I rebooted now it might work. Unfortunately, I don't have the luxury of testing that at the moment.

Steps are simple:
1. Run winscp.exe
2. Double-click desired session.
3. Watch connection attempt.
4. Watch Error prompt appear.

Attached is a screenshot during the attempt. Note that each attempt's last step is actually "Using username xxxx".[/list][/list]


WinSCP 5.17.8

Error message:
Invalid access to memory.

Stack trace:
(00F89E6E)
(00F8BED6)
(00F88C90)
(000861AF) ntdll.dll
(00072B31) ntdll.dll.KiUserExceptionDispatcher
(00000ED3) krb5_32.dll
(000330C5) krb5_32.dll.krb5_cccol_cursor_next
(0002A4F2) krb5_32.dll.krb5_responder_set_answer
(00021CA9) krb5_32.dll.krb5_cc_select
(000218E9) krb5_32.dll.krb5_cc_select
(000167B6) gssapi32.dll.gss_acquire_cred_with_password
(00023524) gssapi32.dll.gss_acquire_cred_with_password
(00024A23) gssapi32.dll.gss_acquire_cred_with_password
(000128AA) gssapi32.dll.gss_init_sec_context
(00C1D3AB)
(00BF7DF4)
(00C0134D)
(00BCF7EA)
(00BCF8DD)
(00D09790)
(00D08673)
(00D03631)
(00D02F71)
(00D8B0D5)
(00CC2AF7)
(00CBDA54)
(000BCF6B)
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(000665F2) ntdll.dll.RtlGetAppContainerNamedObjectPath
(000665BF) ntdll.dll.RtlGetAppContainerNamedObjectPath
Authentication log (see session log for details):
Using username "<redacted>".
S
Kernel 3.10.0-862.3.3.el7.x86_64 on an x86_64


Authentication failed.

Status: unknown_rel_addr

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.