Using Office 2007 in a mixed Office environment can corrupt Excel files if precautions are not taken by end-users and IT. This is particularly evident when “round-tripping” (i.e. converting formats back and forth) between XML and older Microsoft file types. Lack of compatibility with older versions can lead to corrupt data as a result of formula errors and blank cells due to distorted formatting.
Microsoft Answers
Microsoft has taken several steps to dealing with compatibility issues between Office 2007 and older Office versions. Measures to improve compatibility include: