It isn't possible to verify the file as it is written because the buffers and caches in the write process aren't flushed to disk until after the file is closed. Why can't Macrium Reflect validate the data as it is written? Any discrepancy between the two values indicates that the image file is corrupt or cannot be read back reliably. When the file is read back the hash value is recalculated and compared with the original hash in the index. This hash value is saved in the index of the image file. When an image is created each block of data (generally 64K but may be larger depending on the partition size) has an MD5 hash created after it is read from the disk and before it is written to the image file. This is always outside of the control of Macrium Reflect as the OS will report a write without any error. If data is read back with a different MD5 hash to that that was generated when the data was written, it is guaranteed to be corrupt. This guarantees that the same block of data cannot generate a different message digest (hash) value. Macrium Reflect uses the unmodified code from the reference implementation of the RSA Data Security MD5 message-digest algorithm. ![]() How does Macrium Reflect check the data integrity? The most likely suspect is your backup media - but memory and motherboard faults can also cause this issue. ![]() Quite simply, it means that data that was written to the backup or image file is not the same as is read back from the same file.Įrrors of this type are symptomatic of a computer system with a marginal hardware problem. This article explains what happens during the image verification process and how to troubleshoot problems with your system. The vast majority of Macrium Reflect users will never encounter a single verification issue. We estimate that less than 1 in 1,000 systems have problems that lead to image file corruption. Though they do happen, verification errors are extremely rare.
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