Congratulations—you finally got up to actually making backups of your data. If you think it’s a “run and forget” ordeal, though, you’re very, very wrong.
Here’s what you need to do right after your backup is done.
Verify file integrity with checksums
The progress bar is full, but that doesn’t mean that the backup is okay and fully functioning. Operating systems frequently report a successful file copy even when underlying hardware or software issues have compromised the actual data payload. This phenomenon, often referred to as silent data corruption or bit rot, can occur due to faulty cables, degrading storage sectors, or transient memory errors during the transfer process. To definitively ensure that your backup is an exact replica of your source material, you must verify file integrity using checksums.
A checksum acts as a unique digital fingerprint for a specific file, generated by running the file’s raw binary data through a cryptographic hash function, such as SHA-256 or MD5. When you process a file through one of these algorithms, it outputs a fixed-length string of alphanumeric characters. Even the most microscopic alteration to the file—such as a single flipped binary bit—will result in a completely different hash value.
Immediately after copying your data to the backup destination, you must calculate the checksums for both the original files and the newly created backup copies. By comparing these two sets of alphanumeric strings, you can mathematically prove whether the data is identical. If the destination hash perfectly matches the source hash, the integrity of your backup is cryptographically verified, confirming that no corruption occurred during the transmission or writing phases. Conversely, a mismatched checksum immediately alerts you to a corrupted transfer, allowing you to delete the flawed copy and re-initiate the backup process before a true disaster forces you to rely on damaged data.
Perform a test restore
A common axiom in the cybersecurity and data administration industries states that an untested backup is merely a theoretical concept. It’s harsh, but it’s true. The ultimate goal of copying data is not simply to store it, but to retrieve it successfully when the primary system fails. Therefore, performing a test restore immediately after a backup is probably the most important thing you need to do. Checksums verify the integrity of the raw files, but it’s ultimately a superficial test. A proper test restore verifies the integrity of the entire recovery mechanism.
Backup software often relies on complex cataloging systems, proprietary container formats, and encryption algorithms to compress and secure your data. If the software’s index becomes corrupted, or if an encryption key is lost or malformed, the perfectly preserved raw data inside the archive remains completely inaccessible. To conduct a proper test restore, you must attempt to extract the copied files back into a readable format.
This restoration should be directed to a separate sandbox environment or an alternate directory, rather than overwriting your live production data. Overwriting active data during a test introduces the severe risk of replacing perfectly functioning files with a potentially flawed backup. During this test, you should open the restored files using their native applications to ensure they load without errors and retain their original formatting and content.
Successfully executing this procedure provides empirical evidence that your disaster recovery protocol is functional. It also familiarizes you with the restoration interface, eliminating panic and technical confusion during an actual data loss emergency where every second of downtime carries an operational cost.
Disconnect offline backups
Maintaining a persistent connection between your primary systems and your backup storage introduces a catastrophic vulnerability to your entire data infrastructure. Once the backup process is fully verified, the immediate subsequent action must be to physically and logically disconnect the offline backups from the host network. This practice establishes an air gap, a fundamental security measure that isolates your critical data from both digital and physical threat vectors.
In the modern threat landscape, ransomware and sophisticated malware are specifically engineered to seek out and encrypt not only your primary drives but also any connected peripheral devices, network-attached storage, and mapped cloud directories. If your external hard drive remains plugged into your computer via a USB port, or if your backup server remains accessible over the local area network, malicious software will effortlessly traverse that connection to destroy your safety net simultaneously with your primary data.
Aside from regular targeted cyberattacks, maintaining a continuous physical connection exposes your backup hardware to electrical hazards. A severe power surge, a lightning strike, or a catastrophic failure of your computer’s power supply unit can easily send a fatal electrical spike through connected data cables, permanently damaging the storage controller and magnetic platters of an attached external drive. By physically unplugging the data and power cables of your backup media, or by rotating tape cartridges out of their drives and into secure storage, you sever the pathways required for these disasters to propagate.
Stephan is the sports journalist for the Maple Grove Report.
