Whenever I defragment my hard drive there is always one file that cant be defragmented, called ODBC.ini, I was wondering if anyone knows what this is and if its a problem or not.
ODBC stands for "Open DataBase Connectivity" and is an API (Application Programming Interface) for database formats. In a nutshell it allows programs to 'talk' to various databases (such as Access and Oracle) via a single common API. The ODBC.ini file is just a small text file containing the settings for this. Unless you are a programmer it really won't concern you
Normally the reason files can't be defragmented is because they are in use by the OS. Why just the ODBC.ini is a bit of a mystery, but it really won't matter. So, basically, I wouldn't worry in the least - it's not important!