Incomplete File Uploads

In some cases, uploading files or folders can be interrupted. There are several situations that may cause interruptions:

• Unstable internet connection
• Accidentally closing the web browser
• Accidentally switching off the computer
• Accidentally closing the FTP client application

Incomplete uploads in the web interface

If you upload a very big file (more than 4 GB, for example), connectivity interruptions can cause an upload error. Once your internet connection is restored and the web interface is opened and working again, you will see an .incomplete version of the file. Our software supports upload resume. You can upload your file again in the same location and the upload will pick off where it left off. When the upload is complete, the .incomplete suffix on the file name will be removed.

Incomplete uploads in the FTP client

If you are using an FTP client rather than our web interface, we also support resuming uploads of partially transferred files. If for some reason your FTP connection failed during uploading, it will leave behind a partial file. In your account, you will see a smaller file size than expected. Once you recognize the error, log back into your FTP client again and the upload should pick up where it left off. Otherwise, your FTP client may give a message with the option to resume. Choose it and your upload will continue.

.filepart file in WinSCP

WinSCP stores the file being transferred to a temporary filename first, renaming it to the target name only once the transfer successfully finishes.

• If the transfer is interrupted, on the next attempt (either manual or automatic), WinSCP automatically detects the partial/temporary file and offers you the option to resume the transfer (or can even resume automatically).
• While updating an existing file, the original version of the file exists during the whole transfer. This is particularly useful when updating frequently accessed files on websites.
• If the server runs a process that automatically picks new files and processes them, it can be configured to ignore distinct names of temporary files. It prevents the process from picking an incomplete file, while it’s uploaded.

If your transfer is interrupted, a partial file (with .filepart extension) remains in the target folder. After you try to transfer the file a second time, WinSCP looks for the partial file. If it finds a partial file, it offers you a chance to resume the transfer (the confirmation can be disabled). To configure transfer to the temporary file name in scripting, use the -resumesupport switch of file transfer commands. In .NET assembly use TransferOptions.ResumeSupport.