Data Domain, Inc. Cancels Second Quarter Financial Results Release Previously Scheduled for Thursday, July 23, 2009

  Data Domain, Inc. (NASDAQ: DDUP) today
announced it will cancel the release of financial results for the second
quarter ended June 30, 2009 which were previously scheduled to be released
shortly after the close of market on Thursday, July 23rd, 2009 as a result
of the announced majority ownership of Data Domain by EMC. Data Domain has
also cancelled the conference call and live webcast previously scheduled at
5:00 p.m. Eastern Time (2:00 p.m. Pacific Time) that day.

About Data Domain

Data Domain® is the leading provider of deduplication storage systems. Thousands of companies worldwide have purchased Data Domain systems to reduce storage costs and simplify data management. Data Domain delivers the performance, reliability and scalability to address the data protection and nearline storage needs of enterprises of all sizes. Data Domain products integrate into existing customer infrastructures and are compatible with leading enterprise backup and archive software products. To find out more about Data Domain, visit www.datadomain.com. Data Domain is headquartered at 2421 Mission College Blvd., Santa Clara, CA 95054 and can be contacted by phone at 1-866-933-3873 or by e-mail at [e-mail].

Note: Data Domain, the Data Domain logo and Global Compression are trademarks or registered trademarks of Data Domain, Inc. All other trademarks used or mentioned herein belong to their respective owners.

Ed Luboja Director of Communications Data Domain, Inc. +1.203.210.7404 [e-mail]