Error Starting

I've been using WinSCP for a few months now in an app to transfer files.
The application checks the database periodically and if new data is there it creates a file and transfers it.

It was working fine for a while, but I am now getting the error:

Timeout waiting for WinSCP to respond - WinSCP has not responded in time. There was no output. Response log file C:\************.xml was not created. This could indicate lack of write permissions to the log folder or problems starting WinSCP itself.

I don't always get the error and have set session.DebugLogPath and session.XmlLogPath to locations that can be written to. And the system regularly writes to the locations.

I also upgraded to use the latest version, but that also didn't seem to help.

Attached is a log if it helps.

If anyone has any ideas that would be helpful.

Not sure if this helps, but the error is occurring on the line:
Here's the code upto that point:
Access to the directory should not be the issue as it is working sometimes. But I cannot workout what's causing it to occasionally fail.

How are you running your application? From a task scheduler? How often does the problem occur? Did you try turning off your antivirus? Isn't the machine overloaded at the time the problem occurs? Did you try setting longer Session.Timeout?
https://winscp.net/eng/docs/message_library_timeout_waiting_to_respond

Thanks for the ideas.

The application is being run as a scheduled task. Under an admin User with 'Run with highest privileges' ticked.

Antivirus is active, but the app and application folders are on the ignore list.

The issues seams to occur more often then not at the moment, but I cant see any pattern. Which is odd as it ran fine for weeks initially.

I have now increased the timeout in both the sessionoptions and session to 2 minutes, and will see if that helps.

It only runs 2-3 times a day so will take a while to see if it has helped.

I've had it running for a few days, and again see that is has failed a couple of times.

Each time is when it's trying to open the session. Does anyone know what could be causing this?
It now has 6 minutes between trying to open the session and the error "Timeout waiting for WinSCP to respond - WinSCP has not responded in time" being logged

Does it still say "Response log file C:\************.xml was not created."? Please post new debug log.

Yep, it does. But it can create the attached debug log in the same directory, so I don't think it's a rights issue.
I've also had a look in eventviewer, but cant find anything related at the same time.

It got triggered 6 times today, 4 worked and 2 didn't. And I can't see an obvious reason.

If there is anything I should check please let me know.

Thanks

Were it timing out always, it could be some of the problem described here:
https://winscp.net/eng/docs/message_library_timeout_waiting_to_respond
but I have no explanation why it would be timing out only sometimes.