Backup job doesn't detect connection loss, stalled


Using on various Windows 7/10 systems.

I’ve noticed this a few times, and it’s a bit troublesome.
As I’m migrating systems over to Duplicati, not all sites have the best internet/wifi, and I’ve also had to restart the FTP server on occasion.

However, more often then not, when the FTP/internet connection is lost or interrupted (from either end), Duplicati doesn’t seem to detect this or just appears to sit in progress all night. Eventually I notice it, kill the process remotely and it restarts itself, resuming the upload as if nothing happened.

Any thoughts on what I could check for this?


Hmm, Duplicati should report warnings when it fails to connect and then retry a couple of times. The exact behavior probably depends on where it is in the process but there should definitely be warning logs on the live data page


It’s typically in the middle of the FTP transfer. I’ve made a couple adjustments and will see how it handles it on the next run.

As far as the live log goes, there is typically no updated info, just shows the typical progress info, but then nothing while it’s stalled. No errors, retry attempts, etc.

The one I just ran that prompted this post had lost its wifi connection for a minute or two and then came back. I killed the FTP session from my server end, but Duplicati never saw this (presumably because it had lost/regained internet), and just sat there until I killed it in task manager and started it again.


Is this different from the issue you “resolved” with a 10MB volume size here?

When this happens do you see anything “telling” in the “Sever state properties” of the About -> “System info” tab?


I’m running Version and it’s exhibiting the same issue.

In my case the internet connection at the remote (receiving) end sometimes drops in the middle of a backup, sometimes for several minutes. Everytime this happens the backup jobs on the backup clients just hangs and never continues when connectivity resumes nor times out and just remains stuck at the interrupted point. We need to manually cancel the job and Duplicati will then start the next job.

I hope there is a fix for this.


Hi @PhoenixAlpha, welcome to the forum!

What are the last log entries (both in the job and “main” log) before the stall? Are you also using an FTP destination?

Until we can narrow down a specific cause for these stalls you may want to look at adjusting the retry count and delay parameters such as the ones below to better fit your environment. Note that depending on the actual issue they may not help, but it’s worth a try.

--retry-delay (default 10 seconds)
After a failed transmission, Duplicati will wait a short period before attempting again. This is useful if the network drops out occasionally during transmissions.
Default value: “10s”

--number-of-retries (default 5)
If an upload or download fails, Duplicati will retry a number of times before failing. Use this to handle unstable network connections better.
Default value: “5”



The remote end is an SFTP server.

I will try your suggestions and if it happens again, will try and get you the log entries.




I’m having a similar issue backing up ~350 GB to Amazon drive on Windows 10, Duplicati I’ve been running the “Profiling” live log in the GUI to see if I can catch an error when it stops uploading. There is no error, it just stops.

Here is the server current Amazon Drive server state from the System Info page:

lastEventId : 966
lastDataUpdateId : 23
lastNotificationUpdateId : 8
estimatedPauseEnd : 0001-01-01T00:00:00
activeTask : {“Item1”:10,“Item2”:“8”}
programState : Running
lastErrorMessage :
connectionState : connected
xsfrerror : false
connectionAttemptTimer : 0
failedConnectionAttempts : 0
lastPgEvent : {“BackupID”:“8”,“TaskID”:10,“BackendAction”:“Put”,“BackendPath”:“”,“BackendFileSize”:52339133,“BackendFileProgress”:35848192,“BackendSpeed”:11312,“CurrentFilename”:“D:\My Documents\Archive\From Old HDD\Liz\Desktop\CDs\worship songs\Christian - The Air I Breathe.mp3”,“CurrentFilesize”:6676865,“CurrentFileoffset”:819200,“Phase”:“Backup_ProcessingFiles”,“OverallProgress”:0,“ProcessedFileCount”:38267,“ProcessedFileSize”:83854368440,“TotalFileCount”:53058,“TotalFileSize”:428380769688,“StillCounting”:false}
updaterState : Waiting
updatedVersion :
updateReady : false
updateDownloadProgress : 0
proposedSchedule : []
schedulerQueueIds : []
pauseTimeRemain : 0

I have amazon-consistency-delay at 60s, number-of-retries at 25 and retry-delay at 30 seconds.
Is there a different log file I should be generating?


OK, found a new entry in the Profiling Live log:

Mar 17, 2018 1:08 PM: Cannot open WMI provider \localhost\root\virtualization\v2. Hyper-V is probably not installed.
Mar 17, 2018 1:08 PM: Using WMI provider \localhost\root\virtualization\v2
Mar 17, 2018 1:08 PM: Cannot find any MS SQL Server instance. MS SQL Server is probably not installed.
Mar 17, 2018 12:13 PM: CommitAddBlockToOutputFlush took 00:00:00.091

Is there something missing from my Windows install? I’ve seen this error before, but the backup continued without issue.


Unless you are specifically working with virtual machines I don’t think this is anything to worry about.

Just to verify, your issue is the same as the OP where a loss in connection to your destination causes a stall in the backup from which it never recovers?


No virtual machine here.

I don’t know if I’m losing connection, but the symptoms are the same. A stall in the Backend Event:PUT function, with no warning or change in files remaining or size to upload.


I don’t suppose this happens at about the same place / file on the backup every time, does it?


:frowning:, no. Still trying to do my first upload to Amazon drive. Although it’s been running fine for > 1 day, with little issues. I had to restart it once over the last 2 days due to a “Stream Request Timeout”. But I haven’t seen the pause in about 2 days.


Yay? :wink:   



I believe that I’m experiencing the same issue. I’m on Arch Linux, running I’m in the middle of trying to do a large backup to S3 over a slow and not entirely reliable Wimax connection (urgh). I have to restart the duplicati service several times a day because it just gets “stuck” as described. From the front-end, the symptoms are that the progress bar stops displaying an upload rate, and checking my wifi connection reveals that there’s no longer any outbound traffic.

I’ve turned on verbose logging to a file and I see no error reported, the last entry is a “Checking file for changes”, and then nothing. Sever state properties look like this:

lastEventId : 77
lastDataUpdateId : 2
lastNotificationUpdateId : 0
estimatedPauseEnd : 0001-01-01T00:00:00
activeTask : {"Item1":2,"Item2":"2"}
programState : Running
lastErrorMessage :
connectionState : connected
xsfrerror : false
connectionAttemptTimer : 0
failedConnectionAttempts : 0
lastPgEvent : {"BackupID":"2","TaskID":2,"BackendAction":"Put","BackendPath":"","BackendFileSize":38909,"BackendFileProgress":0,"BackendSpeed":-1,"BackendIsBlocking":true,"CurrentFilename":"/home/lucian/Music/Cat Stevens/Remember_ The Ultimate Collection/08 Matthew & Son.m4a","CurrentFilesize":4871046,"CurrentFileoffset":2048000,"Phase":"Backup_ProcessingFiles","OverallProgress":0,"ProcessedFileCount":51515,"ProcessedFileSize":101522367438,"TotalFileCount":63792,"TotalFileSize":165070252186,"StillCounting":false}
updaterState : Waiting
updatedVersion :
updateReady : false
updateDownloadProgress : 0
proposedSchedule : [{"Item1":"2","Item2":"2018-03-24T12:00:00Z"}]
schedulerQueueIds : [{"Item1":3,"Item2":"2"}]
pauseTimeRemain : 0

My system logs for the period don’t show the connection dropping but it’s possible that there was some more substantial packet loss/latency, and this would be on the other side of the router so wouldn’t necessarily cause the wifi connection to fail explicitly. I’m basically running with the default settings for everything. I can try dropping the upload volume size but it’s still concerning to me that duplicati is just hanging in this situation rather than either retrying its way out of it or failing explicitly.