Link: https://old.reddit.com/r/DataHoarder/comments/1vqyejm/psa_macrium_reflect_does_not_verify_cloned_data/

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The original was posted on /r/datahoarder by /u/Archivist_Goals on 2026-08-17 17:16:03+00:00.

For a long time, I had assumed that cloning Source Drive A to Clone Drive B would incorporate a checksum calculation during the "verification" phase that it performs. But apparently, this is not the case. I'm currently running Reflect Workstation v10.

Wanting to take fixity of data more seriously lately, it dawned on me what "verifying" actually meant when a clone job completes. So, I reached out to Macrium support, and they set the record straight: They don't verify data with any kind of fixity.

You could hash and compare after the fact. But the live source/OS VSS will continue changing, so hashing it afterward would not necessarily represent the state Macrium cloned. And I suppose one could create a per-file hash manifest. But that's not very elegant and far more work.

I've been paying for and using MR for over a decade and have been using it without issue. But this seems like a real deal-breaker. Suggestions? Any other serious alternatives?

The full exchange with Macrium support below. Happy to provide email screenshots if necessary.

Me: At any point during cloning, does Reflect calculate a checksum, CRC, or cryptographic hash over data read from the source or written to the destination?

Macrium: No, we don't verify the data in any way.

Me: If so, what algorithm and granularity are used—sector, cluster, block, partition, or whole disk?

Macrium: Not applicable.

Me: During the stage displayed as "Verifying" or "Verifying File System," does Reflect physically reread the destination and compare it with the source or with previously calculated values?

Macrium: No. As the name implies, it verifies the supported source file system.

Me: If the destination is reread, does this cover every copied sector or cluster, and what happens when a mismatch occurs?

Macrium: For RDC, both the source and destination file systems are read to determine which data has been modified. Only the modified data is then read from the source and copied to the destination for RDC. No other data is reread from the destination.

Me: Does a successful Forensic Sector Copy certify byte-for-byte identity? Exactly which address ranges are covered: partition contents, unused filesystem space, inter-partition/unallocated sectors, partition-table structures, and any HPA/DCO areas?

Macrium: For the Forensic option, the clone is created from the start of the partition to the end, sector by sector.

Me: Does the verification behavior differ when cloning under full Windows/VSS versus Rescue Media?

Macrium: No, both verify the supported source file system. In normal Windows, the VSS volume is used for supported file systems, whereas direct volume access is used in Rescue Media.