Blackboard allows you to export the Grade Centre from your course, so that you can work on it offline (in Excel for example) and import again at a later date. The process is very easy, but there is one, quite serious, problem.
Many of our student IDs, which start with the year in which the student first registered, being with a 0 digit (zero). When the exported file from Blackboard is opened in Excel, Excel thinks that the student IDs are numbers, and removes any leading zeroes. So, the student number 08123456 (for example) becomes the number 8,123,456. This leads to problems when you try to reconcile the student IDs with other data, or when you try to import the file back to Blackboard.
The solution is to import the file into Excel (rather than just opening it), and to indicate that the Username and Student ID fields contain text, not numbers. This sounds more complicated than it actually is!
I have prepared a very quick screencast to demonstrate how to perform the export from Blackboard and import into excel. Please take a look.