Detected non-empty blocksets with no associated blocks

Wifi failed while a backup was running on a Windows 10 machine and this message came out:

“Detected non-empty blocksets with no associated blocks!”

which kept appearing if I tried to restart the operation.

Then I tried a database repair but it wouldn’t work. What am I supposed to do other than starting everything from scratch?

This is the contents of the log file:

May 19, 2019 10:06 PM: Result
MainOperation: Repair
RecreateDatabaseResults: null
ParsedResult: Success
Version: 2.0.4.5 (2.0.4.5_beta_2018-11-28)
EndTime: 19/05/2019 22:06:37 (1558296397)
BeginTime: 19/05/2019 22:06:23 (1558296383)
Duration: 00:00:14.3883605
Messages: [
2019-05-19 22:06:23 +02 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Repair has started,
2019-05-19 22:06:24 +02 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Started: (),
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Completed: (376 bytes),
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.Operation.FilelistProcessor-RemoteUnwantedMissingFile]: removing file listed as Temporary: duplicati-20190519T175513Z.dlist.zip.aes,
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.Operation.FilelistProcessor-SchedulingMissingFileForDelete]: scheduling missing file for deletion, currently listed as Uploading: duplicati-bff92596d0fbd4969950399f791eebe12.dblock.zip.aes,

]
Warnings:
Errors:
BackendStatistics:
RemoteCalls: 1
BytesUploaded: 0
BytesDownloaded: 0
FilesUploaded: 0
FilesDownloaded: 0
FilesDeleted: 0
FoldersCreated: 0
RetryAttempts: 0
UnknownFileSize: 0
UnknownFileCount: 0
KnownFileCount: 376
KnownFileSize: 19722258472
LastBackupDate: 01/01/0001 1:00:00 (-62135596800)
BackupListCount: 0
TotalQuotaSpace: 0
FreeQuotaSpace: 0
AssignedQuotaSpace: -1
ReportedQuotaError: False
ReportedQuotaWarning: False
ParsedResult: Success
Version: 2.0.4.5 (2.0.4.5_beta_2018-11-28)
Messages: [
2019-05-19 22:06:23 +02 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Repair has started,
2019-05-19 22:06:24 +02 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Started: (),
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.BasicResults-BackendEvent]: Backend event: List - Completed: (376 bytes),
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.Operation.FilelistProcessor-RemoteUnwantedMissingFile]: removing file listed as Temporary: duplicati-20190519T175513Z.dlist.zip.aes,
2019-05-19 22:06:36 +02 - [Information-Duplicati.Library.Main.Operation.FilelistProcessor-SchedulingMissingFileForDelete]: scheduling missing file for deletion, currently listed as Uploading: duplicati-bff92596d0fbd4969950399f791eebe12.dblock.zip.aes,

]
Warnings:
Errors:

I had no clue what this message meant and how to fix things. I tried to recreate the database but then I got this message “No file lists found on the remote destination”.
Finally the only way was to delete EVERYTHING from the destination and start from scratch.

Now, after almost 3 weeks only 10 Gb were left to be uploaded and I got the same message about non-empty blocksets again.
I wonder if I will ever complete this backup in my lifetime.
Does anyone have any idea about what I could to and not lose the already uploaded files?

I got this error trying to start the second backup. Repaired the database and was able to start it again, but trying to launch third backup give the same error.

Tested with Windows 10 + 2.0.4.18_canary_2019-05-12