I recently had long email conversation with one of the blog reader who was struggling with installing SQL Server 2012 RC0 installation. I just thought I will publish what we have done and how we solved problem so if you are facing the same issue, you can avoid the same.
Though our conversation was very long – I have kept only relevant conversation here.
User: While installing the SQL Server 2012 RC0 the error which is displayed is: File format is not valid.
Pinal: Download the iso format idea again.
User: Downloaded the iso media and extracted it again into C Drive and attempted the installation – still the same error.
Pinal: What is the tool you are using to extract the file?
User: (Some tool)
Pinal: Use alternate iso extractor tool or winrar to extract file.
User: It worked!
The original media was all fine. However, when user was using a software which extract the files from ISO to folder, it was corrupting few files. Well, if you face this issue remember to attempt new software to extract your file. If that does not work, try one more time to download the file.
Reference: Pinal Dave (http://blog.SQLAuthority.com)