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Do invalid date headers on import affect deduplication?

  • Type: Knowledgebase
  • Date changed: one year ago
Solution #00006063


All Barracuda Message Archivers, All Firmware Versions

Often, third party tools, including backup restore tools or message conversion tools from email systems other than Microsoft Outlook and Exchange, create invalid date headers in PST files they generate.  When importing these files with invalid date headers, the Barracuda Message Archiver retains the original source data (.eml format) in its permanent storage. 

In general, customers should not be concerned about the impact of deduplication on the completeness of the message store.  All deduplication operations are applied against a complete message, including all date headers.  As such, deduplication should not cause a unique item to be discarded in error.  


  • If the deduplication algorithm were presented with another copy of the exact same email with the exact same (but invalid) date header, it would be deduplicated consistent with the behavior of identical emails with valid headers. 
  • If the deduplication algorithm were presented with another copy of the message but with a valid header, both the copies with the invalid header and the valid header would be retained even if the rest of the headers were identical.

For more questions about the behavior of the Barracuda Message Archiver deduplication (also known as "Single Instance Storage," please contact Barracuda Networks Technical Support.

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