I have WinSCP ver. 3.7.5. build 294.
Here's the situation.
I've uploaded some part of a "some_file.ext" to my server using usual ftp client and have stopped for some reason.
Now I'm trying to resume uploading this file using WinSCP (note that there is no ".filepart" extension in the file name on the server). WinSCP asks me whether I want to start uploading from the very beginning or want to append. I answer "append". After - another question something like this: "...If you want to resume uploading this file, press NO". I'm prerssing NO and everything goes just fine.
Now I want to stop this process once again and press Cancel.
After that I have no my file or even any part of the file on the server!!! Deleted?!
I've tested this several times from my work and from home - seems to be a stable situation.
P.S. If I resume uploading when a file on a server is with special ".filepart" extension - everything goes fine no matter how many times I stop and then resume uploading.