O&O DiskImage 21:
Backup Software for Windows

An Image is a “copy” of your drive or partition. This “copy” contains all information taken from the original. A special feature of an image is that the file format is especially compressed and takes up much less disk space than the original. The more often you create images of your drive, the less you need worry about data loss. Should data on the original drive be lost or damaged, you can restore your last image with all its data onto your computer. With just a few clicks of the mouse, you can recover the original status of your drive before the last imaging.

A drive is a reserved area of the hard disk. Multiple drives can be found on a hard disk. In the following text, the term “drive” will be used to depict (single) partitions as well as logical drives in expanded partitions. Drives are used, for example, to separate documents from programs. A division in two partitions has become generally accepted.

• Drive C: for operating systems and programs
• Drive D: for documents, e.g. photos, Office documents, music, etc.

This makes it easier to image data using data imaging products such as O&O DiskImage.

In the event of an emergency, many users try to protect their digital photos, office files or videos by simply making a copy of the data and saving it to an external hard disk, CD or DVD. Problems then arise in the course of time when folders are changed and items deleted in the false assumption that a copy exists elsewhere.

The huge advantage with an Image is that it takes up much less space than a copy of your data. Using special algorithms, it is also able to recognize and save just the changes made since the previous image – so-called follow-up images. This way you can easily manage your Images and when disaster strikes, simply restore your lost data with a few mouse clicks.

For imaging and restoring, it is important to know which drives (partitions) your data is saved on. Generally you can find out over the context menu of a folder or file under Properties, e.g. D:My filesHoliday.

• Note: Data saved on your Desktop are normally on drive C:, the system partition. Please be aware that you are unable to restore a system partition with O&O DiskImage Express. If you wish to image data from the Desktop with O&O DiskImage Express, please move the data to another partition, e.g. your data partition.
• Note on the shortcut symbol: The arrow symbol indicates a shortcut, meaning the data itself is not stored at this location, rather the symbol acts as a “link” to the data. In the context menu you can see where the content of the folder is stored, e.g F:Fotos.

If you delete the symbol, you only erase the shortcut to the data, and not the data itself.

• You should image an intact system
• We recommend regular imaging (once a month minimum). The more regular you carry this out, the more up-to-date the data is contained within those images

• System drive (Windows), mostly Drive C:
• All remaining data drives where private and business data, e.g. customer data, photo collections or music is stored.

• Not on the same hard disk where the imaged drive is located
• Ideally on an external hard disk
• DVD

The trial version is fully functional and has no restrictions

• For restoring the system partition.
• When your operating system will no longer start.

O&O DiskImage does not block drives by default during imaging. You can therefore continue working and make changes. The working memory buffer is however restricted. You can see how much is available in the Cache Status Display. See User’s Guide.

Note: To maintain the maximum available working memory buffer, please close all applications before and during the procedure, for example defragmentation or copy processes.

Important: Should you go over the available working memory, the current changes will be written direct to the source drive. This makes the image inconsistent and may render it unusable. In such cases you should load the image after the procedure is finished and check it for errors.

Under Tools you can find the function Convert Image File. This enables you to change certain properties and content of the image retrospectively – see User’s Guide”.

Example: I have created an image of several drives but want to create a separate image of just one of those drives. Follow the instructions below:

• Under Tools select Convert Image File.
• Select the image using Add and then select the drive you wish to separately image.
• After confirming, click Start.

A new image will now be created. The old image remains unaltered.

The O&O DiskImage Premium and Professional is compatible with 11 and 10. The O&O DiskImage Server Edition supports 11, 10, Server 2016, Server 2019, Server 2022 and Server 2025.

Connect the O&O DiskImage To Go boot and backup media containing the backup to be restored to your computer. Start the computer (you may need to change the boot order in the BIOS to start from the external boot and backup media, please refer to the operating instructions of your computer / motherboard) with the O&O DiskImage To Go boot and backup media. On the boot medium start screen that opens, please click on the “1-Button Restore” icon. O&O DiskImage automatically detects the backup on the connected O&O DiskImage To Go boot and backup media and offers you the option to restore this backup. Simply follow the instructions in O&O DiskImage to restore the backup to your computer within a very short time. Of course you can also restore the backup on a new computer, for instance if you have replaced your old PC.

Fortress Mode is a unique feature in O&O DiskImage 21 Premium Edition that provides maximum isolation and security when performing backups.

When enabled, Fortress Mode allows the software to run in a completely isolated Windows environment, ensuring that backups are created without interference from other applications or processes. This isolation makes it possible to perform forensic-level backups, capturing an exact image of the current state of all system storage sectors.

You have two ways to use Fortress Mode:

Integration into the Windows Recovery Environment (WinRE):
Fortress Mode can be integrated into your system’s recovery environment, allowing you to launch O&O DiskImage directly from your PC, even if the main Windows OS is not functioning properly.

Bootable Medium Creation:
You can also create a bootable USB or CD/DVD containing O&O DiskImage. This lets you boot the software externally and perform backups or restorations independently of the installed operating system.

Both options provide full flexibility—whether you’re restoring your original system or transferring your backup to new hardware.