I've checked with a Microsoft friend and he's having trouble finding details about this problem as well. He commented about my upload attempts where it looks like 97% of the upload is successful (even for uploads much larger than 100 Mb) before the error occurs. He's wondering if some other check is failing as the file reaches its completed upload and generating an incorrect error message.

Does anyone have any idea who to contact about the WebDAV API that might have a clue regarding this problem? Thanks.

I believe it's a limit of OneDrive WebDAV API. I do not think you can do anything about it. It's likely a server-side limit. Nothing you can change locally.

My question is related to the WebDAV mode in the 5.19.2 (Build 11614) version of WinSCP. I’m running WinSCP on an 8-core, 32 Gb RAM PC running Windows 8.1 Pro. I followed the instructions on your website https://winscp.net/eng/docs/guide_microsoft_onedrive for connecting to my Microsoft OneDrive account using WinSCP. The login and access of the files appear to be working correctly.

My question involves the inability to upload files that are larger than approximately 100 Mb. When I attempt to upload a file larger than 100 Mb, at around 97% of the upload I receive the error message “413 Request Entity Too Large”. I believe this is a WebDAV error and not one produced by WinSCP. I am able to download much larger files without issues (I’ve successfully downloaded a 20 Gb file without problems). It is only when I attempt to upload files that the error occurs.

I’ve done some online reading and found a discussion about the registry setting HKLM\SYSTEM\CurrentControlSet\Services\WebClient\Parameters\FileSizeLimitInBytes. I’ve checked it and it is set to 50000000, as the articles describe. The literature says this setting has something to do with WebDAV download limits, but that doesn’t seem to be the case since I’m able to download much larger files than that without issues.

I believe the problem is not necessarily directly related to WinSCP itself, but I was hoping someone might have an idea how to fix this issue since you are familiar with what it takes to connect to a OneDrive account. Thank you for your help.