ERROR 550, but only on one of my computers

[confusedmonkey]

I work with about 4 different PCs. All Windows 10. All running the latest FileZilla client with the same configs. Some are hardwired. Some are wireless (the problem pc is exclusively wireless). One of these computers has major issues uploading to the same server that I access routinely on other computers.

On the computer in question, some files transfer with no issue. Eventually though - and pretty often - I will get the 550 error. Resetting the que and it continues to fail. I can upload the same file on another computer and not have a problem. Until this computer, I've never run into an issue like this over several years of using FileZilla and servers running Windows, Linux, etc.

One other thing that might be a clue. When the file(s) fail to transfer, it is sometimes an overwrite. In that case the file(s) only appears to be on the server when using FileZilla on the problem computer. When accessing it via another PC, the file does not appear in the directory on the server. Refreshing on the computers doesn't change this.

Seems it can happen to any file, regardless of size, location or type.

I can try to requeue, but the file continues to fail. If, however I wait an arbitrary amount of time and then requeue - it may suddenly upload with no issue. This, along with the random nature of the failure itself has made it very difficult to debug. Which is why I'm here, looking for any advice I can get.

So again to be clear, all computers:

- Same network
- Same OS
- Same Filezilla
- Same FTP Account
- Same FZ Settings, as far as I can tell


Only this one PC has issues. Am I missing some critical setting? Is there some configuration outside of FileZilla that might cause this behavior?

Portion of the log from a transfer of many files, where only two didn't make it:

Code: Select all

Response:    150 Opening BINARY mode data connection.
Trace:    CFtpRawTransferOpData::ParseResponse() in state 6
Trace:    CControlSocket::SendNextCommand()
Trace:    CFtpRawTransferOpData::Send() in state 7
Trace:    CFtpControlSocket::OnReceive()
Response:    226 Transfer complete.
Trace:    CFtpRawTransferOpData::ParseResponse() in state 7
Trace:    CFtpControlSocket::ResetOperation(0)
Trace:    CControlSocket::ResetOperation(0)
Trace:    CFtpRawTransferOpData::Reset(0) in state 7
Trace:    CFtpFileTransferOpData::SubcommandResult(0) in state 7
Trace:    CFtpControlSocket::ResetOperation(0)
Trace:    CControlSocket::ResetOperation(0)
Trace:    CFtpFileTransferOpData::Reset(0) in state 7
Status:    File transfer successful, transferred 8,085 bytes in 1 second
Trace:    CFtpControlSocket::FileTransfer()
Trace:    CControlSocket::SendNextCommand()
Trace:    CFtpFileTransferOpData::Send() in state 0
Status:    Starting upload of C:\Dev\test\admin.js
Trace:    CFtpChangeDirOpData::Send() in state 0
Trace:    CFtpControlSocket::ResetOperation(0)
Trace:    CControlSocket::ResetOperation(0)
Trace:    CFtpChangeDirOpData::Reset(0) in state 0
Trace:    CFtpFileTransferOpData::SubcommandResult(0) in state 1
Trace:    CFtpControlSocket::OnReceive()
Response:    550 The process cannot access the file because it is being used by another process.
Trace:    CFtpRawTransferOpData::ParseResponse() in state 4
Trace:    CFtpControlSocket::ResetOperation(2)
Trace:    CControlSocket::ResetOperation(2)
Trace:    CFtpRawTransferOpData::Reset(2) in state 4
Trace:    CFtpFileTransferOpData::SubcommandResult(2) in state 7
Trace:    CFtpControlSocket::ResetOperation(2)
Trace:    CControlSocket::ResetOperation(6)
Trace:    CFtpFileTransferOpData::Reset(6) in state 7
Error:    Critical file transfer error
Trace:    CFtpControlSocket::FileTransfer()
Trace:    CControlSocket::SendNextCommand()
Trace:    CFtpFileTransferOpData::Send() in state 0 

[botg]

550 The process cannot access the file because it is being used by another process.

On the server machine, some process still has the file opened. Make sure to close the file in all other processes on the server.

[confusedmonkey]

Yeah, I get that part. That wasn’t the extent of the mystery though. The mystery is why it might only affect one computer.

If the same files uploaded over the same network with the same FTP account, using the same software on any other computer – NEVER – has any 550 errors, but one computer consistently does – then maybe there is something about this computer that's doing something wonky.

This pattern has been the case for hundreds of transfers a day, from multiple devices, over the span of years.

I was hoping someone might have some idea about how to debug this or what might be causing this one computer to consistently have issues during the transfer process. Why would only one computer trigger the server to behave differently towards it?

[botg]

Could there be some AV product holding the file hostage for some time?