O&O AutoBackup is a Windows application for backing up personal files and synchronizing folders. It can preserve earlier copies of documents, photos and project files, or maintain matching working folders, depending on the mode selected. Its backups recover file data; they do not recreate a complete Windows installation with its applications and settings.
How O&O AutoBackup keeps file versions
O&O AutoBackup organizes work into pairs. A backup pair connects one or more source folders to a destination and retains its own schedule, file filters, retention rules and security settings. Separate pairs can therefore protect a frequently edited document folder and a larger photo collection on different terms. Folder exclusions and file-type filters narrow what each job processes.
In Backup mode, new and changed files travel from the source to the destination. When a newer copy replaces a stored file, the previous copy remains under a dated name. History belongs to individual files: an unchanged file does not produce another version simply because a backup runs. Deleting a source file does not immediately remove its stored copies, so recovery can reach back before an unwanted edit or deletion.
Automatic storage management keeps recent versions close together and gradually reduces older history to more widely spaced copies. Optional age and per-file limits give further control over storage growth. These rules apply to historical copies while preserving the current copy of each file.
Folder synchronization
The other modes produce folders intended for direct use rather than a managed recovery history. O&O AutoBackup distinguishes their direction and treatment of deletions:
| Mode | Folder behavior |
|---|---|
| Copy | Adds and updates files from left to right. A file removed from the left stays on the right. |
| Merge | Combines files in both directions without propagating deletions. A surviving copy can return a deleted file to the other folder. |
| Mirror | Makes the right folder match the left, including removing right-side files that no longer belong in the source. |
| Two-way | Carries additions, edits and deletions between two active working folders. |
These modes do not retain Backup mode’s version history. A preview exposes proposed operations, including removals. When both sides have edited the same file, the conflict policy can retain both copies, choose the newest, prefer either side, or skip the file. Removed and replaced synchronization files normally go to the Windows Recycle Bin, which has its own capacity and cleanup rules.
Backup destinations
Targets include internal disks, USB drives, network shares, WebDAV services and S3-compatible storage. A network destination can retain its server, share and sign-in information so later runs reconnect without repeating that configuration. Different pairs can send different data sets to local or remote storage.
O&O AutoBackup records the identity of a removable destination rather than relying solely on its Windows drive letter. Reconnecting the assigned drive can trigger its job even when Windows gives it a different letter. An unrelated disk that inherits the previous letter is not treated as the intended destination.
Automatic runs
Jobs can run continuously after file changes, at regular intervals, on daily, weekly or monthly schedules, or only when started manually. Continuous operation waits for a quiet period after changes instead of starting on every temporary write. Connection-triggered operation suits a backup disk that is attached only when needed.
Scheduled work depends on O&O AutoBackup remaining active, including through its notification-area mode. Battery, idle and metered-network settings control when automatic work is allowed. Deferred jobs catch up when their destination and operating conditions permit.
The Home page shows the last and next run, while progress reports and logs identify files that failed, unavailable destinations and other pending work. Pausing a run leaves earlier completed backups available.
OneDrive files
O&O AutoBackup can select personal and business OneDrive accounts configured for the current Windows user. Its handling of Files On-Demand determines whether a backup contains only locally available data or also collects online-only files.
Online-only content can be downloaded and kept locally, downloaded for backup and then returned to its online-only state, or skipped. Collecting it requires bandwidth and temporary disk space. A destination outside the protected OneDrive account provides a separate copy whose retained history can precede a change that has already spread through cloud synchronization.
Backup encryption
Backup mode can encrypt individual files with AES-256-GCM. Optional name hiding stores files under random names and keeps their folder structure in an encrypted index, concealing information that readable file names would otherwise reveal. Synchronization modes leave their working folders directly editable and do not support this backup encryption.
Encryption and name hiding are chosen before the backup first runs. Changing that design requires a new pair and destination. Recovery uses the password or the recovery key generated during setup; without either, encrypted data cannot be restored.
File recovery
The restore browser displays folders as they existed at a selected point in time. Users can recover an entire backup or selected items into a chosen folder, including an earlier copy of a file that has since disappeared. Restoring creates copies and leaves the stored backup history in place.
O&O AutoBackup can also open an existing backup without its original pair configuration. An optional recovery application stored alongside the backup provides another route on a compatible Windows PC, without installing or licensing the full product. For unencrypted backups without hidden names, current and dated files remain accessible through File Explorer.
