> For the complete documentation index, see [llms.txt](https://docs.movebot.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.movebot.io/using-movebot/transfer-execution-and-cutover/deltas-and-changes.md).

# Deltas and Changes

### Keeping Your Data Up to Date

In active environments, it’s common for files to be added or updated during a migration. Movebot’s **Delta Migration** feature helps keep your destination up to date by copying **only the files that have been added or modified** since the last transfer.

***

### How Delta Migrations Work

Delta Migrations compare the **source and destination** using each file’s **modification time (modtime)**.\
Only files that are **new** or have a **more recent modtime** on the source will be transferred. This reduces duplication and speeds up the process by skipping files that haven't changed.

{% hint style="warning" %}
Important: **Movebot does not delete or move files at the destination**

If you rename files or move them to a new directory in the source, Movebot will see them as "new" files. This means that they won't be moved in the destination, and instead will be migrated again. 

If you delete files at the source, a delta migration **will not** delete them in the destination. 

To avoid duplication or confusion, we recommend **avoiding major restructuring** during the migration process. 
{% endhint %}

***

### Running a Delta Migration

Delta Migrations increase **scan time**, but reduce **transfer time** by focusing only on what’s changed.

You can only launch a Delta Migration **after your Full Migration** run. To do this: 

1. Open your project.
2. Select the transfer(s) you want to run a Delta for.
3. Click **Run Action**.
4. Choose **Start Delta Migration**.<br>

We recommend running a Delta Migration for your Cutover to catch files that were created or updated since your Full Migration. You can also run a Delta Migration to resolve certain errors. See further information on this at [Failures and Errors](/using-movebot/transfer-execution-and-cutover/failures-and-errors.md). &#x20;

### Running a delta migration as your initial transfer

If you already have content in your destination tenant because of user access or a partially-completed migration, you may want to start with a Delta Migration instead of a Full Migration.&#x20;

In this scenario, you can enable the "**Include only Changed Files/Objects**" setting. This setting forces Delta Migrations and uses the delta migration process outlined above for all transfers. \
\
To force Delta Migrations across all runs:

1. Go to **Step 4** in your project settings.
2. Enable the **“Include only Changed Files/Objects”** option.