Backups fail with error: Object reference not set to an instance of an object


#1

Hello, first time poster, so please be patient as I learn the culture and expectations of this forum! :pray: :wink:

First, thanks for the community that makes Duplicati. I’m a Crash Plan Home refugee and I selected Duplicati as it’s replacement in part due to the active community here.

Now on to my issue:

I had an working scheduled backup that seems to have been failing since 30 Nov 2018. I’m hoping the community here can assist me in troubleshooting.

The current error I receive:
Object reference not set to an instance of an object

I’m currently running Duplicati - 2.0.4.5_beta_2018-11-28
My client is running Ubuntu 16.04 and my destination is running Ubuntu 18.04

What logs/messages would be helpful in proceeding with troubleshooting?

Thanks in advance for your help!


#2

You could go to “About -> Show logs”, find where this error is and send us the stacktrace. Another option is to go to “the backup item -> Show logs” and paste the entire log of this run


#3

Thanks @mikaelmello. What is the best way for me to send the logs? Just screen-scrape from the Duplicati GUI log page and attach here? Or should I be zipping and attaching some how?

Sorry the basic question. I’m just trying to understand the preferred process on this forum.


#4

Which way works best for you, I guess


#5

Also, the logs seem to be dated back on 30 Nov (last sucessful backup). Not sure the best way to get you the logs that contain the failure.


#6

Below are the last logs in the GUI (from date of last successful backup):

>Nov 30, 2018 1:48 AM: Result
>DeletedFiles: 23842
>DeletedFolders: 4
>ModifiedFiles: 766
>ExaminedFiles: 374329
>OpenedFiles: 14383
>AddedFiles: 13565
>SizeOfModifiedFiles: 4964271492
>SizeOfAddedFiles: 614454602
>SizeOfExaminedFiles: 1338051869616
>SizeOfOpenedFiles: 5588780961
>NotProcessedFiles: 0
>AddedFolders: 21
>TooLargeFiles: 0
>FilesWithError: 52
>ModifiedFolders: 0
>ModifiedSymlinks: 0
>AddedSymlinks: 1
>DeletedSymlinks: 0
>PartialBackup: False
>Dryrun: False
>MainOperation: Backup
>CompactResults:
>    DeletedFileCount: 0
>    DownloadedFileCount: 0
>    UploadedFileCount: 0
>    DeletedFileSize: 0
>    DownloadedFileSize: 0
>    UploadedFileSize: 0
>    Dryrun: False
>    MainOperation: Compact
>    ParsedResult: Success
>    EndTime: 11/30/2018 1:47:11 AM (1543564031)
>    BeginTime: 11/30/2018 1:23:29 AM (1543562609)
>    Duration: 00:23:42.6879820
>    BackendStatistics:
>        RemoteCalls: 100
>        BytesUploaded: 2451168883
>        BytesDownloaded: 83776983
>        FilesUploaded: 95
>        FilesDownloaded: 3
>        FilesDeleted: 0
>        FoldersCreated: 0
>        RetryAttempts: 0
>        UnknownFileSize: 0
>        UnknownFileCount: 0
>        KnownFileCount: 56380
>        KnownFileSize: 1476753186748
>        LastBackupDate: 11/30/2018 12:00:00 AM (1543557600)
>        BackupListCount: 74
>        TotalQuotaSpace: 0
>        FreeQuotaSpace: 0
>        AssignedQuotaSpace: -1
>        ReportedQuotaError: False
>        ReportedQuotaWarning: False
>        ParsedResult: Success
>DeleteResults:
>    DeletedSets: []
>    Dryrun: False
>    MainOperation: Delete
>    ParsedResult: Success
>    EndTime: 11/30/2018 1:47:11 AM (1543564031)
>    BeginTime: 11/30/2018 1:20:51 AM (1543562451)
>    Duration: 00:26:19.7781910
>RepairResults: null
>TestResults:
>    MainOperation: Test
>    Verifications: [
>        Key: duplicati-20181129T060000Z.dlist.zip.aes
>        Value: [],
>        Key: duplicati-i811a33d375324b78a62063716ced9233.dindex.zip.aes
>        Value: [],
>        Key: duplicati-bf93f767977ea4c6491ef6505cc6a4697.dblock.zip.aes
>        Value: []
>    ]
>    ParsedResult: Success
>    EndTime: 11/30/2018 1:48:22 AM (1543564102)
>    BeginTime: 11/30/2018 1:48:11 AM (1543564091)
>    Duration: 00:00:10.4274630
>ParsedResult: Error
>EndTime: 11/30/2018 1:48:22 AM (1543564102)
>BeginTime: 11/30/2018 12:00:00 AM (1543557600)
>Duration: 01:48:22.3571260
>Messages: [
>    No remote filesets were deleted,
>    Compacting not required
>]
>Warnings: [
>    Failed to process path: /home/jake/.cache/tilda/locks/lock_3042_0 => Access to the path "/home/jake/.cache/tilda/locks/lock_3042_0" is denied.,
>    Failed to process path: /home/missy/.ICEauthority => Access to the path "/home/missy/.ICEauthority" is denied.,
>    Failed to process path: /home/missy/.Xauthority => Access to the path "/home/missy/.Xauthority" is denied.,
>    Failed to process path: /home/missy/.bash_history => Access to the path "/home/missy/.bash_history" is denied.,
>    Failed to process path: /home/missy/.xsession-errors => Access to the path "/home/missy/.xsession-errors" is denied.,
>...
>]
>Errors: []

#7

But here is the error on the popup:

Error while running lothar - home folder and shared drive

Object reference not set to an instance of an object

DismissShow


#8

Can you go to “About -> Show logs” and show what’s there?


#9

Thanks @mikaelmello! That was where I needed to look. Here is the latest log from “About --> Show Logs”

**Dec 10, 2018 12:13 AM: Failed while executing "Backup" with id: 1**
>System.NullReferenceException: Object reference not set to an instance of an object
>  at Duplicati.Library.Utility.FileBackedList`1[T].Add (Duplicati.Library.Utility.T value) <0x41ee3230 + 0x002a2> in <filename unknown>:0 
>  at Duplicati.Server.WebServer.RESTMethods.CommandLine+LogWriter.WriteLine (System.String value) <0x41f3d0b0 + 0x00123> in <filename unknown>:0 
>  at System.IO.TextWriter.WriteLine (System.String format, System.Object arg0, System.Object arg1) <0x7f23a37d4f10 + 0x0009b> in <filename unknown>:0 
>  at Duplicati.CommandLine.ConsoleOutput.WriteMessage (Duplicati.Library.Logging.LogEntry entry) <0x41f4a7d0 + 0x000d4> in <filename unknown>:0 
>  at Duplicati.Library.Main.MultiMessageSink.WriteMessage (Duplicati.Library.Logging.LogEntry entry) <0x41f4a750 + 0x0004e> in <filename unknown>:0 
>  at Duplicati.Library.Main.ControllerMultiLogTarget.WriteMessage (Duplicati.Library.Logging.LogEntry entry) <0x41ee2bc0 + 0x000c7> in <filename unknown>:0 
>  at Duplicati.Library.Logging.LogScope.WriteMessage (Duplicati.Library.Logging.LogEntry entry) <0x41dac5c0 + 0x00058> in <filename unknown>:0 
>  at Duplicati.Library.Logging.Log.WriteMessage (LogMessageType type, System.String tag, System.String id, System.Exception ex, System.String message, System.Object[] arguments) <0x41dabf90 + 0x000c7> in <filename unknown>:0 
>  at Duplicati.Library.Logging.Log.WriteErrorMessage (System.String tag, System.String id, System.Exception ex, System.String message, System.Object[] arguments) <0x41f27380 + 0x0003f> in <filename unknown>:0 
>  at Duplicati.Library.Main.Controller.RunAction[T] (Duplicati.Library.Main.T result, System.String[]& paths, IFilter& filter, System.Action`1 method) <0x41ed6030 + 0x00b3b> in <filename unknown>:0 
>  at Duplicati.Library.Main.Controller.Backup (System.String[] inputsources, IFilter filter) <0x41ed43b0 + 0x002eb> in <filename unknown>:0 
>  at Duplicati.Server.Runner.Run (IRunnerData data, Boolean fromQueue) <0x41ec4680 + 0x010a3> in <filename unknown>:0

#10

I searched “Object reference not set to an instance of an object” in the forum. I found a few hits, but they didn’t seem to have a direct correlation to my symptoms, and they didn’t seem to have a solution.

Any other suggestions folks?


#11

Hello @jake, welcome to the forum!

Was the job working with 2.0.4.5 then stopped or did the errors start after an update?

(FYI I edited your posts by adding ~~~ around the entire to make them easier to read.)


#12

Thanks for the formatting tip @JonMikelV

I’m not sure if I had a good back up on my new code version. Can you tell me where I can find the log location for Duplicati my Linux box so I can look for my upgrade date?

Since the version I’m on (2.0.4.5_beta_2018-11-28) is dated so close to my last backup date (2018-11-30), I suspect I did not have a successful backup on this version of code. But obviously I’d like to confirm that!

Thanks to the community for all the help!


#13

If you get email notifications of your backups then the version should be in there, otherwise the Duplicati logs are stored in the databases - “global” errors in the main db and job specific ones in the job dbs.

For job logs, open the job menu and click “Show log”. In there you should see timestamps with a one or two word summary - click on one of them to expand for details. Here’s what it looks like expanded:
image

Global logs can be found on themain menu -> About -> Show log page.


#14

It appears that I had good backups from at least 27 Nov through 30 Nov with 30 Nov being the last successful backup. I’m still not sure what day I updated to 2.0.4.5_beta_2018-11-28 because my “global” log appears to only go back to 1 December.


#15

I think the About --> Show log page is mainly for issues that arise, so sometimes nothing there is good news. Backup job logs happen even if all goes well, and newer Duplicati versions include a Version field, such as:

ParsedResult: Success
Version: 2.0.4.5 (2.0.4.5_beta_2018-11-28)
EndTime: 12/11/2018 7:19:14 PM (1544573954)
BeginTime: 12/11/2018 7:15:21 PM (1544573721)
Duration: 00:03:53.3900462

This should help you figure out what backups were on 2.0.4.5, and get summary information on their results. Debugging a specific problem like the “Object reference” one may need much more. Stack trace was a start. Sometimes setting up extremely heavy logging like –log-file-log-level=Profiling (or Information for less) helps. Reproducible small test cases are best, because then maybe some developer can take a really close look…


#16

Thank you @ts678 for the tips.

My latest successful backup is from 30 Nov and does not have a version listed.

    ParsedResult: Success
    EndTime: 11/30/2018 1:47:11 AM (1543564031)
    BeginTime: 11/30/2018 1:23:29 AM (1543562609)
    Duration: 00:23:42.6879820

So I am assuming that I have never successfully backed up using version 2.0.4.5_beta_2018-11-28

I’m a little embarrassed that I don’t remember which version I was using prior to 2.0.4.5_beta_2018-11-28, but I think it was 2.0.3.3

I’m not sure I understand your suggestion about stack trace or heavy logging. Are you suggesting I try a new separate backup with a smaller payload in order to somehow troubleshoot my existing situation?

I appreciate the help, but I’m just not sure what is being suggested as a next step!


#17

Do you have any logs in the per-job log area (where that log came from) that came from a failure (or at all)?

Seeing 2.0.4.5 fail on its first run would confirm the introduction date, and possibly provide more information, however logs at this summarized level only go so far. A simple-to-setup next-level set of logs will be to see if live logging at About --> Show log --> Live --> Information shows any interesting lead-up to the failure. Stack traces provide good snapshots at moment of failure, but are not good at the time-sequence that led there…

Sometimes logs will show both the sequence (such as what processing was happening) and the final ending. Let’s try something relatively light first, like the Information level live log above (it can use a different browser tab), to see if that helps get context, then go from there. There is no exact recipe to progressing to answers.

Ordinarily I would prefer not trying to solve problems on systems I’ve never used, but with the others who’ve been in this, maybe progress can be made. Sometimes much can be gained from experimentation by those reporting the problem, and setting up the simplest possible scenario that fails would possibly enable a deep analysis by the right parties that would lead to a bug fix. Getting a well-written issue filed in GitHub with exact steps is a good way to ensure an issue is tracked, and get it in line for the actual code fix by the developers. Forum support tends to look less at code, and more at seeing if there’s any other way to get things running.

Please post a sample of the ordinary highly-summarized job logs after failure began, meaning after 30 Nov.
Let’s try live log at Information level too. Feel free to look at other levels, but Profiling can be overwhelming. Please see if you can find a simple test case of tiny backup to the same system, with minimal extra options.


#18

Thanks @ts678 for the info.

I kicked off another backup job and collected the following live log at informational level

  • Dec 16, 2018 4:14 PM: The operation Backup has started
  • Dec 16, 2018 4:14 PM: Fatal error
{"ClassName":"Duplicati.Library.Interface.UserInformationException","Message":"Unexpected difference in fileset version 73: 4/6/2018 6:25:30 AM (database id: 2), found 295603 entries, but expected 295604","InnerException":null,"HelpURL":null,"StackTraceString":" at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (Int64 blocksize, Int64 hashsize, Boolean verifyfilelists, IDbTransaction transaction) &lt;0x4165d020 + 0x010a7&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Backup.BackupDatabase+&lt;&gt;c__DisplayClass32_0.&lt;VerifyConsistencyAsync&gt;b__0 () &lt;0x4165cec0 + 0x0003b&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;&gt;c__DisplayClass3_0.&lt;RunOnMain&gt;b__0 () &lt;0x4165ce40 + 0x00019&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;DoRunOnMain&gt;d__2`1[T].MoveNext () &lt;0x4165c510 + 0x003ff&gt; in &lt;filename unknown&gt;:0 \n--- End of stack trace from previous location where exception was thrown ---\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f6648c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) &lt;0x7f6648bff6b0 + 0x000a7&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) &lt;0x7f6648bff630 + 0x0006b&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) &lt;0x7f6648bff5e0 + 0x0003a&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.GetResult () &lt;0x7f6648bff5c0 + 0x00012&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.BackupHandler+&lt;RunAsync&gt;d__19.MoveNext () &lt;0x415c2000 + 0x01256&gt; in &lt;filename unknown&gt;:0 \n--- End of stack trace from previous location where exception was thrown ---\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f6648c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 \n at CoCoL.ChannelExtensions.WaitForTaskOrThrow (System.Threading.Tasks.Task task) &lt;0x414b6af0 + 0x000e2&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.BackupHandler.Run (System.String[] sources, IFilter filter) &lt;0x415bb760 + 0x0001f&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Controller+&lt;&gt;c__DisplayClass13_0.&lt;Backup&gt;b__0 (Duplicati.Library.Main.BackupResults result) &lt;0x415b4880 + 0x000af&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Controller.RunAction[T] (Duplicati.Library.Main.T result, System.String[]&amp; paths, IFilter&amp; filter, System.Action`1 method) &lt;0x41516600 + 0x00597&gt; in &lt;filename unknown&gt;:0 ","RemoteStackTraceString":null,"RemoteStackIndex":0,"HResult":-2146233088,"Source":"mscorlib","ExceptionMethod":null,"Data":null}
  • Dec 16, 2018 4:14 PM: The operation Backup has failed with error: Unexpected difference in fileset version 73: 4/6/2018 6:25:30 AM (database id: 2), found 295603 entries, but expected 295604
{"ClassName":"Duplicati.Library.Interface.UserInformationException","Message":"Unexpected difference in fileset version 73: 4/6/2018 6:25:30 AM (database id: 2), found 295603 entries, but expected 295604","InnerException":null,"HelpURL":null,"StackTraceString":" at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (Int64 blocksize, Int64 hashsize, Boolean verifyfilelists, IDbTransaction transaction) &lt;0x4165d020 + 0x010a7&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Backup.BackupDatabase+&lt;&gt;c__DisplayClass32_0.&lt;VerifyConsistencyAsync&gt;b__0 () &lt;0x4165cec0 + 0x0003b&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;&gt;c__DisplayClass3_0.&lt;RunOnMain&gt;b__0 () &lt;0x4165ce40 + 0x00019&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;DoRunOnMain&gt;d__2`1[T].MoveNext () &lt;0x4165c510 + 0x003ff&gt; in &lt;filename unknown&gt;:0 \n--- End of stack trace from previous location where exception was thrown ---\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f6648c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) &lt;0x7f6648bff6b0 + 0x000a7&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) &lt;0x7f6648bff630 + 0x0006b&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) &lt;0x7f6648bff5e0 + 0x0003a&gt; in &lt;filename unknown&gt;:0 \n at System.Runtime.CompilerServices.TaskAwaiter.GetResult () &lt;0x7f6648bff5c0 + 0x00012&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.BackupHandler+&lt;RunAsync&gt;d__19.MoveNext () &lt;0x415c2000 + 0x01256&gt; in &lt;filename unknown&gt;:0 \n--- End of stack trace from previous location where exception was thrown ---\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f6648c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 \n at CoCoL.ChannelExtensions.WaitForTaskOrThrow (System.Threading.Tasks.Task task) &lt;0x414b6af0 + 0x000e2&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Operation.BackupHandler.Run (System.String[] sources, IFilter filter) &lt;0x415bb760 + 0x0001f&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Controller+&lt;&gt;c__DisplayClass13_0.&lt;Backup&gt;b__0 (Duplicati.Library.Main.BackupResults result) &lt;0x415b4880 + 0x000af&gt; in &lt;filename unknown&gt;:0 \n at Duplicati.Library.Main.Controller.RunAction[T] (Duplicati.Library.Main.T result, System.String[]&amp; paths, IFilter&amp; filter, System.Action`1 method) &lt;0x41516600 + 0x00597&gt; in &lt;filename unknown&gt;:0 ","RemoteStackTraceString":null,"RemoteStackIndex":0,"HResult":-2146233088,"Source":"mscorlib","ExceptionMethod":null,"Data":null}

Hopefully this is what you were suggesting!


#19

It’s a fine shot at the second item. I’m still looking forward to first (logs of original error) and third (test case). Actually, the surprising thing about what you posted is that this isn’t the original error. Did that also happen? “Unexpected difference in fileset” is being reported elsewhere but I’d prefer to look into the original problem, even though it seems to be far less seen (which is one reason I would like some experimentation for item 3).

One thing I was hoping for appears to be missing in the live log, and only present in --log-file logs. Example:

2018-12-16 18:02:34 -05 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started
2018-12-16 18:02:34 -05 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
Duplicati.Library.Interface.UserInformationException: Unexpected difference in fileset version 0: 11/28/2018 12:04:56 PM (database id: 42), found 0 entries, but expected 1
   at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency(Int64 blocksize, Int64 hashsize, Boolean verifyfilelists, IDbTransaction transaction)
   at Duplicati.Library.Main.Operation.Backup.BackupDatabase.<>c__DisplayClass32_0.<VerifyConsistencyAsync>b__0()
   at Duplicati.Library.Main.Operation.Common.SingleRunner.<>c__DisplayClass3_0.<RunOnMain>b__0()
   at Duplicati.Library.Main.Operation.Common.SingleRunner.<DoRunOnMain>d__2`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__19.MoveNext()
2018-12-16 18:02:36 -05 - [Information-Duplicati.Library.Modules.Builtin.SendMail-SendMailComplete]: Email sent successfully using server: smtp://smtpauth.earthlink.net:587/?starttls=always

in a --log-file log at --log-file-log-level=Information has prefixes after the time to say what’s going on, and also shows the actual detail of the stack trace. This gives me both the path leading to the error and the error itself. Live log has about the same number of steps, but without detail. I guess in the future I should ask for log-files.

* Dec 16, 2018 6:02 PM: The operation Backup has failed with error: Unexpected difference in fileset version 0: 11/28/2018 12:04:56 PM (database id: 42), found 0 entries, but expected 1

* Dec 16, 2018 6:02 PM: Email sent successfully using server: smtp://smtpauth.earthlink.net:587/?starttls=always

* Dec 16, 2018 6:02 PM: Fatal error

* Dec 16, 2018 6:02 PM: The operation Backup has started

Let me see if I can find anything more from what I have, while you work the other parts and comment on the live log post – does this have any relationship to the original problem? Is it happening before that one can? Typically people seem to either see this immediately on upgrade to 2.0.4.5 on some old version (your case), or get it on version 0 which is the one just made – and I have a test case on how that one can be recreated.


#20

I think this is what you mean (from Stored Logs)

Dec 1, 2018 12:47 AM: Failed while executing “Backup” with id: 1

Duplicati.Library.Interface.UserInformationException: Unexpected difference in fileset version 73: 4/6/2018 6:25:30 AM (database id: 2), found 295603 entries, but expected 295604 at Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency (Int64 blocksize, Int64 hashsize, Boolean verifyfilelists, IDbTransaction transaction) &lt;0x40a796e0 + 0x010a7&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Operation.Backup.BackupDatabase+&lt;&gt;c__DisplayClass32_0.&lt;VerifyConsistencyAsync&gt;b__0 () &lt;0x40a79660 + 0x0003b&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;&gt;c__DisplayClass3_0.&lt;RunOnMain&gt;b__0 () &lt;0x40a79620 + 0x00019&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Operation.Common.SingleRunner+&lt;DoRunOnMain&gt;d__2`1[T].MoveNext () &lt;0x40a78e90 + 0x003ff&gt; in &lt;filename unknown&gt;:0 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f3120c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) &lt;0x7f3120bff6b0 + 0x000a7&gt; in &lt;filename unknown&gt;:0 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) &lt;0x7f3120bff630 + 0x0006b&gt; in &lt;filename unknown&gt;:0 at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) &lt;0x7f3120bff5e0 + 0x0003a&gt; in &lt;filename unknown&gt;:0 at System.Runtime.CompilerServices.TaskAwaiter.GetResult () &lt;0x7f3120bff5c0 + 0x00012&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Operation.BackupHandler+&lt;RunAsync&gt;d__19.MoveNext () &lt;0x40a4c000 + 0x012f2&gt; in &lt;filename unknown&gt;:0 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () &lt;0x7f3120c016d0 + 0x00029&gt; in &lt;filename unknown&gt;:0 at CoCoL.ChannelExtensions.WaitForTaskOrThrow (System.Threading.Tasks.Task task) &lt;0x408e6580 + 0x000e2&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Operation.BackupHandler.Run (System.String[] sources, IFilter filter) &lt;0x40a494c0 + 0x0001f&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Controller+&lt;&gt;c__DisplayClass13_0.&lt;Backup&gt;b__0 (Duplicati.Library.Main.BackupResults result) &lt;0x40a45bb0 + 0x000af&gt; in &lt;filename unknown&gt;:0 at Duplicati.Library.Main.Controller.RunAction[T] (Duplicati.Library.Main.T result, System.String[]&amp; paths, IFilter&amp; filter, System.Action`1 method) &lt;0x40a389e0 + 0x00597&gt; in &lt;filename unknown&gt;:0