What do you mean by "under the hood"? Can you please be more specific?

By Host I mean the machine where WinSCP runs.

Originally I am getting: WinSCP.SessionRemoteException
but under the hood SessionLocalException is raised.

Just to clarify: By "host" – do you mean the server you are connecting to? Or the machine that hosts the service (the machine where WinSCP runs)?

Also now I have noticed the discrepancy between the subject and the original post text. So are you getting SessionLocalException or SessionRemoteException?

In all the cases we had on some computers it was like that:

1. Host restarted
   
2. Service with WinSCP is working and then at some point later on (usually after a month), it stops connecting to FTP server: WinSCP.SessionRemoteException. Service restart doesn't work. Restarting host solves the issue.
   

Does restarting the workstation help? What does "after some time of usage" mean exactly?

Hi,
On some workstations we got that error. The .net process was run on system account.
After investigation we got more detailed error:

Exception: WinSCP.SessionLocalException: WinSCP process terminated with exit code 3. There was no output. Response log file C:\Windows\TEMP\wscp1C14.00E7D730.tmp was not created. This could indicate lack of write permissions to the log folder or problems starting WinSCP itself.

Restarting service didn't help. Changing user account from system to a user with admin rights did solve the error.

From what I have read, it is been a well known error however it has already been solved a long time ago.