File upload using WinSCPnet.dll fails with permission denied error

I'm using Octopus deploy powershell script to upload files using WinSCP.
I'm getting error:
WinSCP.SessionRemoteException: Can't open file '\Boot\BCD'.
The process cannot access the file because it is being used by another process
at WinSCP.OperationResultBase.Check()
at CallSite.Target(Closure , CallSite , Object )
Why WinSCP is trying to access BCD?

Jhook wrote:

Why WinSCP is trying to access BCD?

We cannot answer that, as we do not even know what your code is doing. Show us your code and a log file (Session.SessionLogPath).