eDiscovery Daily Blog

Date Searching for Emails and Loose Files Can Be Tricky: eDiscovery Best Practices

I recently had a client that was searching for emails and loose files based on a relevant date range.  However, because of the way the data was collected and the way the search was performed, identifying the correct set of responsive emails and loose files within the relevant date range proved to be challenging.  Let’s take a look at the challenges this client faced.


The files were collected by client personnel with the emails placed into PST files and loose files from local and network stores all put into folders based on custodian.  The data was then uploaded and processed using CloudNine’s Discovery Client software for automated data processing and placed into the CloudNine Review platform.

Issue #1

Before they retained us for this project, the client placed copies of loose files into the custodian folders via “drag and drop”.  If you have been reading our blog for a long time, you may recall that when you “drag and drop” files to copy them to a new location, the created date will reflect the date the file was copied, not the date the original file was created (click here for our earlier post on whether a file can be modified before it is created).

As a result, using created date to accurately reflect whether a file was created within the relevant date range was not possible, so, since it was too late to redo the collection, we had to turn to modified date to identify potentially responsive loose files based on date/time stamp within the relevant date range.

Issue #2

With the data processed and loaded, the client proceeded to perform a search to identify documents to be reviewed for responsiveness to the case that included the agreed-upon responsive terms for which either the sent date or the modified date was from 1/1/2014 to present.  Make sense?  In theory, yes.  However, the result set included numerous emails that were sent before 1/1/2014.  Why?

One of the first steps that Discovery Client (and most other eDiscovery processing applications) performs is “flattening” of the data, which includes extracting individual files out of archive files.  Archive files include ZIP and RAR compressed files, but another file type that is considered to be an archive file is Outlook PST.  Processing applications extract individual messages from the PST, usually as individual MSG (individual Outlook message) or HTML files.  So, if a PST contains 10,000 messages (not including attachments), the processing software creates 10,000 new individual MSG or HTML files.  And, each of those newly created files has a created date and modified date equal to the date that individual file was created.

See the problem?  All of the emails were included in the result set, regardless of when they were sent, because the modified date was within the relevant date range.  Our client assumed the modified date would be blank for the emails.


To resolve this issue, we helped the client restructure the search by grouping the terms within CloudNine so that the sent date range parameter was applied to emails only and the modified date range parameter was applied to loose files only.  This gave the client the proper result with only emails sent or loose files modified within the relevant date range.  The lesson learned here is to use the appropriate metadata fields for searching specific types of files as others can yield erroneous results.

So, what do you think?  Have you ever experienced search issues when searching across emails and loose files at once?  Please share any comments you might have or if you’d like to know more about a particular topic.

Disclaimer: The views represented herein are exclusively the views of the author, and do not necessarily represent the views held by CloudNine. eDiscovery Daily is made available by CloudNine solely for educational purposes to provide general information about general eDiscovery principles and not to provide specific legal advice applicable to any particular circumstance. eDiscovery Daily should not be used as a substitute for competent legal advice from a lawyer you have retained and who has agreed to represent you.