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

martin wrote:

Thanks for your report. So you are not able to reproduce the problem anymore?

I can reproduce the problem. It appears every time I construct a new session in the same way as I described.

I suggest that the problem might be the following one. By default it seems to be that WinSCP uses the Microsoft SSPI SECUR32.DLL. This crashes (mybe the 32-bit library does not fit with my 64-bit WinSCP?). Somehow WinSCP detects the failure and excludes SSPI for future tries. From that on the MIT Kerberos GSSAPI64.dll is used instead. This is the library I had inteded to use from the beginning.

Thanks for your report. Are you able to reproduce the problem?
I can see that the difference is probably that in one case SSPI was used, while in the other GSSAPI was used. Do you have any idea why is that? Did you change something on the system meanwhile?

Dear support-team,
I switched on the "Allow GSSAPI credential delegation" and saved my session details. Then I tried to connect and it failed (see attached screen shot WINSCP_bug.png and de_bug.log). Then I closed WinSCP and tried the saved session again. Now it worked (see attached de_nobug.txt which I truncated). Since then it works always.

Sincerely,
Roman Hatzky