Duplicati v2.4.0.100_canary_2026-09-04

This release is a canary release intended to be used for testing.

New Native VSS snapshot provider

This release introduces a new native VSS snapshot provider on Windows that replaces the previous providers. Hyper-V and MSSQL enumeration work with the native provider which is now default.

The new native VSS snapshot provider does not require VCRedist to be installed and works on x86, x64, and Arm64 systems. The existing AlphaVSS and Vanara-based VSS snapshot providers can still be selected (but not on Arm64). They will be removed in a future version as AlphaVSS is no longer maintained and the new native library has fewer dependencies than Vanara.

New WMI VSS snapshot provider

The previously supported WMIC provider has been removed as Windows updates will remove the executable it relies on. Instead a new WMI snapshot provider is added which works similar to WMIC.

The WMI (and WMIC) provider gives a more light-weight VSS functionality, where it does not flush the writers (MSSQL, HyperV, etc) but just ensures a crash-consistent disk snapshot.

If you rely on systems that integrate with VSS, use the Native provider, if you just want to back up locked files, use the WMI provider.

Full-disk backup and VSS snapshots

With this release VSS is now also used for full-disk backups. This is fully transparent and works such that an active snapshot is detected and the full-disk reader will use the snapshot to access the disk contents.

Recovering from an interrupted first backup

Interrupting a first backup previously left the destination in an unrecoverable state: blocks and index files were uploaded, but no filelist was written, so neither backup nor repair could proceed. The recreate logic can now reconstruct a database from the index files alone, so an interrupted first backup can be resumed instead of requiring the destination to be discarded, thanks @JamBalaya56562.

Repair no longer removes metadata

The repair handler previously attempted to fix defective metadata with various reassignment strategies that could silently remove metadata. It now reports the problem and asks the user to run list-broken-files and purge-broken-files, which rewire the metadata while keeping the file content. Detection of zero-length and otherwise defective blocksets has also been improved.

Azure Blob Storage path support

The Azure Blob Storage backend previously ignored the path part of the destination URL and always stored data in the root of the container. The path is now treated as a prefix, so backups can be placed in a subfolder of a container. If you previously used a path in an Azure Blob Storage destination URL, the data was stored in the root; after upgrading, new backups will use the path as a prefix and will not see the previously uploaded files.

Prevent empty machine ID

A startup sequence issue could cause a clean install to report and connect to the console without a machine ID, which could cause various unwanted behaviors.

Linux sleep prevention

Duplicati can now prevent the system from sleeping during backup operations on Linux, similar to the existing support on Windows and macOS.

AppImage .zsync support

This release now has the .zsync file and relevant metadata such that future updates can be done efficiently and automatically by AppImage managers that support it.

--synchronous-upload deprecated

The --synchronous-upload option no longer has any effect and is now marked as deprecated. Existing configurations that set it will continue to load, but a warning is now logged. Use --asynchronous-upload-limit instead.

Default exclude volume information

The System Volume Information folder is now automatically excluded from backups as it cannot be reliably read and cannot be used in a restore process.

Performance and stability updates

Several performance fixes are applied to the local database queries, affecting most operations, mostly by @JamBalaya56562. Many edge cases around unexpected server responses and url encoding issues have also been adressed, thanks @JamBalaya56562.

Detailed list of changes

• Updated all localizations, thanks to all translators
• Added a native VSS snapshot provider, replacing the WMI-based approach
• Fixed Hyper-V and MSSQL enumeration with the native VSS provider
• Added --vss-writer-flush-timeout to control how long to wait for VSS writers
• Used VSS for full-disk backups and automatically excluded System Volume Information
• Hid unsupported VSS options on Arm64
• Added support for recreating a database from an interrupted first backup, thanks @JamBalaya56562
• Changed repair to report defective metadata instead of silently reassigning it
• Improved detection and notification of zero-length and defective blocksets
• Sped up purge-broken-files by reusing the invalid-blocks query
• Added an API endpoint for purging files across backup versions
• Added permission checks for MS365 and Google Workspace so users can verify granted permissions
• Fixed MS365 group classifications and added validation of source and destination provider options
• Added support for a path prefix in Azure Blob Storage destinations
• Fixed --prefix combined with path separators in sync operations
• Fixed a clean install potentially starting with an empty machine ID
• Added sleep prevention support on Linux
• Fixed the destination self-test incorrectly failing on OpenStack when a probe file was already gone, thanks @JamBalaya56562
• Fixed Google Cloud Storage not detecting a delete of a missing file
• Fixed Google Cloud Storage URL encoding that broke authentication
• Fixed OneDrive browsing failing on the drive root and not returning folders
• Fixed OneDrive folder names with percent signs or hashes not being reachable, thanks @JamBalaya56562
• Fixed Dropbox folder names with percent signs being decoded twice, thanks @JamBalaya56562
• Fixed SharePoint destination paths containing + being misread, thanks @JamBalaya56562
• Fixed WebDAV destination paths containing + being misread, thanks @JamBalaya56562
• Fixed hostless backend URLs such as dropbox://?authid=... failing to enumerate from the root
• Fixed a Windows source given as a bare drive letter (e.g., C:) resolving to the process working directory instead of the drive root, thanks @JamBalaya56562
• Preserved the fileset timestamp when replacing a missing dlist file during repair, thanks @JamBalaya56562
• Recorded the fileset timestamp in the dlist file so a database recreate keeps it, thanks @JamBalaya56562
• Fixed URL query string values not always being preserved when modifying URLs
• Indexed the verification tables on the compared columns, significantly speeding up remote volume verification, thanks @JamBalaya56562
• Removed a redundant DISTINCT that blocked index lookups in fileset queries, thanks @JamBalaya56562
• Stopped deduplicating twice in the fileset consistency check, thanks @JamBalaya56562
• Made BackendTester re-read the remote folder before abandoning a test run, and accept an already-deleted file during cleanup, thanks @JamBalaya56562
• Cleared the Filen file cache when a write did not come back, preventing stale lookups, thanks @JamBalaya56562
• Re-read the Filejump file list when a delete got no answer, thanks @JamBalaya56562
• Re-read the Drime file list when a delete got no answer, thanks @JamBalaya56562
• Deprecated --synchronous-upload which no longer has any effect, thanks @JamBalaya56562
• Added .zsync files for .appimage releases, enabling delta updates
• Updated System.CommandLine from pre-release to the stable 2.0 release
• Regenerated the libsecret DBus bindings with the latest tooling

Updates to ngclient

• Changed the order for navigation on new backups: source before destination
• Added support for purging files from the UI
• Added support for checking permissions with MS365 and Google Workspace
• Fixed Windows search results having a leading \ prefix, causing empty restores
• Fixed WebDAV destination path normalization, thanks @JamBalaya56562
• Fixed folder filters losing their type while editing, thanks @JamBalaya56562
• Fixed folder exclusions not propagating through the file tree, thanks @JamBalaya56562
• Fixed file attribute exclusions not being preserved when editing, thanks @JamBalaya56562
• Fixed local schedule dates being reset when editing, thanks @JamBalaya56562
• Fixed custom form validator behavior, thanks @JamBalaya56562
• Fixed commandline result polling, thanks @JamBalaya56562
• Hardened HTTP interceptor request handling, thanks @JamBalaya56562
• Fixed the file browser height on the restore page
• Fixed flicker in the Duplicati Storage backup picker
• Fixed connection state being set incorrectly with socket relay
• Migrated to hey-api's modern Angular client, thanks @sp90
• Fixed termination display
• Updated all translations, thanks to all translators