Typically, the root cause is not a logging, it's just a manifestation of the actual problem, that WinSCP does not start. And no, you cannot turn it off, it's necessary for .NET assembly operation.
Please download Process Monitor from:
When you run it, it will ask you to enter filter (if not, use filter toolbar button).
Select "Process Name", "contains", "winscp" => Add => Ok.
Then run WinSCP.
Hopefully some records about the start show up.
The go to File > Save, select "Events displayed using current filter" and PML format (both should be default).
Try to collect the log both for situation when WinSCP works and when it does not.
Email me the .pml files then.