I am having this problem since a few months:
on my home PC (windows 8.1) when I start the Skype desktop app, it logins into my Skype account, but after a second it logs out and shows the starting dialog (see screenshot below), where I must enter my account name and password again to log in. Then everything works until the next time I start Skype when the same problem happens again.
The showed login dialog:
At that time, the Skype credentials disappear from Control Panel / Credential Manager (where they are usually stored and visible, when the Skype login works - see below an example):
I use the same Skype account on my iPhone and iPad and work PC (Windows 7) and there is never an issue.
- reinstalling Skype
- clearing all saved state, including the Skype login credentials in Windows Credential Manager
- updating the Skype app (several updates were released in that time)
The only thing I found was a workaround:
- start Windows
- login to Windows
- open Control Panel / Credential Manager
- start Skype
I am doing this since a month, and it never fails. Today I started Skype without opening Credential Manager first, and bam, it logged me out again.
Currently I have Skype version 8.55
For reference, this is how Credential Manager looks when my Skype login is remembered: