[Solved] Veeam Backup Failed – Cyclic Redundancy Check

As a tech enthusiast, I try to do make sure I back up. Every night, I rely on Veeam to create a reliable backup of my precious photo library, which I store on a dedicated drive. However, one night, disaster struck: Veeam threw a CRC (Cyclic Redundancy Check) error during the backup process. If you’ve ever encountered a CRC error, you know how frustrating it can be. But don’t worry—I’m here to explain what happened, why it happened, and how I fixed it using the chkdsk /r command.

What is a CRC Error?

A CRC error is a type of data integrity error that occurs when the system detects a mismatch between the expected and actual data. In simpler terms, it means that the data being read from the drive doesn’t match what was originally written. This can happen due to various reasons, such as:

• Bad sectors on the drive: Physical damage or wear and tear on the disk can cause data corruption.
• File system corruption: Issues with the file system structure can lead to data being misread or inaccessible.
• Connection issues: Faulty cables or ports can cause data transmission errors.

In my case, the CRC error was likely caused by bad sectors or file system corruption on the drive where my Immich photo library is stored. Immich, being a self-hosted photo backup solution, stores thousands of high-resolution images, so any issue with the drive can have serious consequences.

My First Attempt: chkdsk /f

When I first encountered the CRC error, I turned to the trusty chkdsk (Check Disk) utility in Windows. I ran the command chkdsk /f to fix any file system errors. The /f switch tells chkdsk to fix errors it finds on the disk. However, after running the command, the CRC error persisted. That’s when I realized I needed to dig deeper.

Why chkdsk /f Wasn’t Enough

The /f switch is great for fixing logical file system errors, such as corrupted file tables or directory structures. However, it doesn’t address physical issues with the drive, such as bad sectors. Bad sectors are areas of the disk that can no longer reliably store data due to physical damage or wear. If the CRC error is caused by bad sectors, chkdsk /f won’t be able to resolve the issue.

The Solution: chkdsk /r

This is where the /r switch comes into play. The chkdsk /r command not only fixes file system errors but also scans the entire drive for bad sectors and attempts to recover readable information. Here’s how it works:

1. Locates Bad Sectors: The /r switch scans the drive surface to identify bad sectors.
2. Marks Bad Sectors: Once identified, the bad sectors are marked as unusable, preventing the system from writing data to them in the future.
3. Recovers Data: If possible, chkdsk /r recovers any readable data from the bad sectors and moves it to healthy parts of the drive.

Running chkdsk /r is a more thorough process than chkdsk /f, and it can take significantly longer, especially on large drives. However, it’s often necessary to resolve CRC errors caused by physical drive issues.

How I Fixed My CRC Error

After realizing that chkdsk /f wasn’t enough, I ran chkdsk /r on the drive containing my Immich photo library. The process took several hours, but it was worth it. Here’s what happened:

1. Bad Sectors Were Found: The scan identified several bad sectors on the drive.
2. Data Was Recovered: chkdsk /r successfully recovered the data from the bad sectors and moved it to healthy areas of the drive.
3. Bad Sectors Were Marked: The bad sectors were marked as unusable, preventing further data corruption.

Once the process was complete, I ran my Veeam backup again, and this time, it completed without any CRC errors. My photo library was safe, and I could breathe a sigh of relief.