Topic "WinSCP 5.5.3 timing out | large file transfers..."

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Joined: 2008-11-30
Posts: 10
Location: NY
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 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.
fig2.png (32.74 KB)

Description: (none)


fig1.png (48.65 KB)

Description: First indication of problems completing transfer.


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Joined: 2002-12-10
Posts: 24759
Location: Prague, Czechia
Please attach a full log file showing the problem (using the latest version of WinSCP).

To generate log file, enable logging, log in to your server and do the operation and only the operation that causes the error. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you may email it to me. You will find my address (if you log in) in my forum profile. Please include link back to this topic in your email. Also note in this topic that you have emailed the log.
Martin Prikryl


Hi, I'm having exactly the same problem: timeout at 99% for files of around 40 Mb
Did you find a solution for this?
Thank you

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