I've been using WinSCP for a *loong* time, and, recently (past ~2 years), quite successfully in uploading large-ish files (say, in the 500 meg -> 1.5 Gb range) to one of my cloud accounts (generally, one hosted by box.com). Normally, this works perfectly, but recently (either because of a change in 5.5.3 versus earlier versions, or something on the Box side), this isn't working very smoothly.
I connect to Box using passive ftp with explicit TLS encryption. Port 21 (nothing particularly fancy here). Start the transfer, and then right at the end (say, 99% mark) the status bar for WinSCP reports '99% Uploading (Not Responding' (see attachment, Fig. 1). Then, after 10-15 seconds, I get an error box (see attachment, Fig. 2) saying 'Timeout Detected, Copying files to remote side failed'. If I hit 'Reconnect', then WinSCP connects, and the final bits of the transfer seem to complete.
But, beyond the inconvenience of having to wait and hit the 'Reconnect' button, I have no easy way of determining if the file transfer has in fact completed, or if file integrity hasn't been compromised while WinSCP seems to be hanging.
Any suggestions? Pointsers to the obvious?
Thanks in advance.