Hi Everyone,
I’m using duplicati on a ~136GB dataset on an automatic daily backup schedule with 7D:1D,4W:1W,12M:1M,100Y:1Y retention (I have ~18 versions dating as back as 2022).
I’m currently using v2.0.8.1_beta_2024-05-07 (having upgraded several months ago).
Suddenly, yesterday, my backups started failing with error “Unexpected difference in fileset”.
I find several people reporting same error in the forum, but it’s for different versions and not clear “one size fits all” solution.
I’d obviously like to fix the problem but also take the opportunity to contribute to finding the root cause (and therefore preventing or automatically mitigating such a problem in future versions).
I’ll be happy to follow instructions and share data that may contribute to this.
Could you kindly advice?
For information, I’m a software engineer with software development as well as several years of IT infrastructure management experience, and also curious about duplicati’s internal workings, so do not hesitate to speak very technical.
Thanks,
Gaston
Please find below the detailed error message:
2025-04-19 22:26:12 +09 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
UserInformationException: Unexpected difference in fileset version 6: 2025-01-08 13:37:30 (database id: 61), found 168203 entries, but expected 168207
Unexpected difference in fileset version 3: 2025-03-22 13:54:17 (database id: 99), found 170259 entries, but expected 170263
Unexpected difference in fileset version 2: 2025-03-30 13:42:19 (database id: 103), found 170260 entries, but expected 170264
Unexpected difference in fileset version 1: 2025-04-13 13:11:13 (database id: 106), found 170258 entries, but expected 170262
And the complete log
{
"DeletedFiles": 0,
"DeletedFolders": 0,
"ModifiedFiles": 0,
"ExaminedFiles": 0,
"OpenedFiles": 0,
"AddedFiles": 0,
"SizeOfModifiedFiles": 0,
"SizeOfAddedFiles": 0,
"SizeOfExaminedFiles": 0,
"SizeOfOpenedFiles": 0,
"NotProcessedFiles": 0,
"AddedFolders": 0,
"TooLargeFiles": 0,
"FilesWithError": 0,
"ModifiedFolders": 0,
"ModifiedSymlinks": 0,
"AddedSymlinks": 0,
"DeletedSymlinks": 0,
"PartialBackup": false,
"Dryrun": false,
"MainOperation": "Backup",
"CompactResults": null,
"VacuumResults": null,
"DeleteResults": null,
"RepairResults": null,
"TestResults": null,
"ParsedResult": "Fatal",
"Interrupted": false,
"Version": "2.0.8.1 (2.0.8.1_beta_2024-05-07)",
"EndTime": "2025-04-19T13:26:12.5973108Z",
"BeginTime": "2025-04-19T13:25:38.855818Z",
"Duration": "00:00:33.7414928",
"MessagesActualLength": 1,
"WarningsActualLength": 0,
"ErrorsActualLength": 2,
"Messages": [
"2025-04-19 22:25:38 +09 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started"
],
"Warnings": [],
"Errors": [
"2025-04-19 22:26:12 +09 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error\r\nUserInformationException: Unexpected difference in fileset version 6: 2025-01-08 13:37:30 (database id: 61), found 168203 entries, but expected 168207\n\rUnexpected difference in fileset version 3: 2025-03-22 13:54:17 (database id: 99), found 170259 entries, but expected 170263\n\rUnexpected difference in fileset version 2: 2025-03-30 13:42:19 (database id: 103), found 170260 entries, but expected 170264\n\rUnexpected difference in fileset version 1: 2025-04-13 13:11:13 (database id: 106), found 170258 entries, but expected 170262",
"2025-04-19 22:26:12 +09 - [Error-Duplicati.Library.Main.Controller-FailedOperation]: The operation Backup has failed with error: Unexpected difference in fileset version 6: 2025-01-08 13:37:30 (database id: 61), found 168203 entries, but expected 168207\n\rUnexpected difference in fileset version 3: 2025-03-22 13:54:17 (database id: 99), found 170259 entries, but expected 170263\n\rUnexpected difference in fileset version 2: 2025-03-30 13:42:19 (database id: 103), found 170260 entries, but expected 170264\n\rUnexpected difference in fileset version 1: 2025-04-13 13:11:13 (database id: 106), found 170258 entries, but expected 170262\r\nUserInformationException: Unexpected difference in fileset version 6: 2025-01-08 13:37:30 (database id: 61), found 168203 entries, but expected 168207\n\rUnexpected difference in fileset version 3: 2025-03-22 13:54:17 (database id: 99), found 170259 entries, but expected 170263\n\rUnexpected difference in fileset version 2: 2025-03-30 13:42:19 (database id: 103), found 170260 entries, but expected 170264\n\rUnexpected difference in fileset version 1: 2025-04-13 13:11:13 (database id: 106), found 170258 entries, but expected 170262"
],
"BackendStatistics": {
"RemoteCalls": 0,
"BytesUploaded": 0,
"BytesDownloaded": 0,
"FilesUploaded": 0,
"FilesDownloaded": 0,
"FilesDeleted": 0,
"FoldersCreated": 0,
"RetryAttempts": 0,
"UnknownFileSize": 0,
"UnknownFileCount": 0,
"KnownFileCount": 0,
"KnownFileSize": 0,
"LastBackupDate": "0001-01-01T00:00:00",
"BackupListCount": 0,
"TotalQuotaSpace": 0,
"FreeQuotaSpace": 0,
"AssignedQuotaSpace": 0,
"ReportedQuotaError": false,
"ReportedQuotaWarning": false,
"MainOperation": "Backup",
"ParsedResult": "Success",
"Interrupted": false,
"Version": "2.0.8.1 (2.0.8.1_beta_2024-05-07)",
"EndTime": "0001-01-01T00:00:00",
"BeginTime": "2025-04-19T13:25:38.855818Z",
"Duration": "00:00:00",
"MessagesActualLength": 0,
"WarningsActualLength": 0,
"ErrorsActualLength": 0,
"Messages": null,
"Warnings": null,
"Errors": null
}
}