# How Blober Handles Duplicate Files in Long-Running Backups

> Learn when to resume a Blober task, when to rerun a workflow, and how Local filename deduplication prevents repeated downloads and numbered copies.

## Long Backups Need Two Different Kinds of Protection

A cloud library can take hours or days to copy. During that time, a computer may restart, a network may disconnect, or a provider may ask you to sign in again. You may also want to run the same export later to collect newer files.

Those situations sound similar, but they need different tools:

* **Resume the existing task after an interruption.** Blober keeps that task's progress and does not process its completed records again.
* **Use destination deduplication for a new Local export.** When a new task writes to the same local folder, filename deduplication can skip exact destination filenames that are already there.

Understanding that distinction is the key to avoiding unnecessary transfers.

## Workflow vs Task: What Blober Remembers

A **workflow** is the reusable setup: source, destination, selected folders, filters, and naming rules. Each time you start that workflow, Blober creates a **task** that records the progress of that run.

Within a task, Blober records each source path as it is processed or skipped. If that task is interrupted and later continues, records already marked complete are not processed again.

This task state is stored locally with your workflows. Closing Blober, restarting the computer, or installing a newer version of Blober preserves the existing workflows and task history.

### What to Do After an Interruption

1. Reopen Blober.
2. Find the existing task on the **Progress** page.
3. If it was paused, resume that same task.
4. If it was still pending or running when Blober closed, the app can rediscover it after launch and continue it automatically.
5. Complete any provider login prompt that appears.

Do not start a new task merely because the original task stopped. A new run has its own progress records and is not a continuation of the interrupted run.

This matters especially for long cloud transfers. A provider login may expire during a run; signing in again refreshes access, while the existing task keeps its completed-file state.

## Why a New Local Export Keeps Same-Name Files by Default

When Local is the destination, Blober's default deduplication setting is **None (keep both files)**. If the computed destination path already exists, the new file is saved as `name (1).ext`, then `name (2).ext`, and so on.

That default is deliberate. Two different source items can have the same filename. Google Photos, cameras, and shared folders commonly contain unrelated files named `IMG_0001.JPG`. Silently discarding one would be worse than retaining both.

The tradeoff is that rerunning the same export into the same folder can create numbered copies unless you choose a stricter policy.

## Skip Existing Local Files by Filename

For a repeat export where an exact existing destination filename means "already downloaded," enable Local filename deduplication:

1. Open or create the workflow.
2. Select **Local** as the destination.
3. Open the Local destination options.
4. Set **Deduplication** to **Filename (skip existing file)**.
5. Save and run the workflow.

Blober checks the exact computed destination path before consuming the source file. It repeats that check when claiming the final filename, which also protects against two concurrent transfers racing to create the same path.

See the [Local provider deduplication reference](/kb/docs/providers/local/#option-deduplication) for the setting and its limitations.

> **Caution**
>
> Filename deduplication compares names and paths, not file contents. If two different source files can share a filename, leave the setting at **None (keep both files)** or separate them with folder and naming rules.

## Which Option Should You Use?

| Situation                                                    | Recommended action                                                         |
| ------------------------------------------------------------ | -------------------------------------------------------------------------- |
| Blober, the computer, or the network stopped during a task   | Resume the existing task                                                   |
| A provider asks you to sign in again during a task           | Sign in, then continue the existing task                                   |
| You installed a Blober update during a transfer              | Reopen Blober and continue the existing task                               |
| You intentionally rerun an export into the same Local folder | Enable **Filename (skip existing file)**                                   |
| The source may contain different files with identical names  | Keep **None (keep both files)**                                            |
| The destination is Google Drive or another cloud provider    | Resume the same interrupted task; the Local filename option does not apply |

## Google Photos Reruns Without Numbered Copies

Google Photos is a common case because a large library may take a long time to download and may contain repeated camera filenames.

For an interrupted Google Photos download, continue the existing task. For a deliberate later export into the same local folder, use **Filename (skip existing file)** only when preserving one file per exact destination filename matches your library.

The full setup is covered in [How to Back Up Google Photos Without Google Takeout](/kb/articles/how-to-backup-google-photos-without-takeout/). That guide and the [Local provider reference](/kb/docs/providers/local/#option-deduplication) use the same deduplication setting described here.

## Best Practices for Multi-Day Transfers

* Keep the computer connected to power and avoid moving or disconnecting the destination drive.
* Use a stable destination folder and path template for the whole task.
* Pause before intentionally shutting down if you want manual control over when the task continues.
* After an unexpected restart, reopen Blober before creating anything new and check the existing task first.
* Respond to provider login prompts instead of replacing the workflow.
* Review files marked failed or skipped after completion. A provider may temporarily make an individual file unavailable even though the rest of the transfer completed.

## Frequently Asked Questions

### Will updating Blober erase my workflows or task progress?

No. Installing an update preserves the local database that contains workflows, tasks, and per-record state. Reopen the existing task after the update rather than creating a replacement.

### Does filename deduplication compare file contents?

No. It checks whether the exact destination filename already exists. It does not calculate or compare content hashes.

### Does a skipped file count as complete in the same task?

Yes. Blober saves the reason in the task details and continues with the remaining files. This prevents one unavailable source file or an intentional destination duplicate from blocking the rest of the transfer.

### Can I use Local filename deduplication with Google Drive?

No. It is an option of the Local provider when used as a destination. When Google Drive is the destination, avoid duplicate transfers after an interruption by resuming the original task.

## Get Blober

Blober runs on Windows, macOS, and Linux and is built for transfers that are too large to babysit in a browser.

**[Download Blober at blober.io](https://blober.io)**