You did receive the debug log i sent to you by email?

Still not reproducible?

I cannot reproduce this.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

(I have enabled avi and mp4 attachments)

Workspace is disabled.

It seems that "LastStoredSession=" will be saved to WinSCP.ini but it won't read it when i start WinSCP or want to open a new site.

I have attached a video (i hope it will work this time).
No, mp4 not allowed, avi not allowed. Isn't mp4 and avi common media formats?

I archive the file and now i was able to attach it...

I cannot reproduce the problem.
Can you describe step-by-step what are you doing?

Do you have workspace saving enabled or not?
https://winscp.net/eng/docs/ui_pref_window
(not that it should matter, I just need to know what setup do you have)

It seems that the "New Session" doesn't remember last logged in site. It seems to open at the top on "New site" instead of the last used site.

I'm running WinSCP 5.16 (Dev Build 9651 2019-06-28) and if i try older versions it will remember it.