Make a backup of your Outlook Calendar and Contacts:
1. Open Outlook.
2. Go to File ->(For Outlook 2010, "Open") -> Import and Export -> Select Export to a file -> Click Next -> Select Personal Folder File (.pst) -> Click on your Mailbox Calendar folder. Also check "Include Sub-folders". -> Click Next -> Save the pst file to a secure location and click finish.
3. Depending on your preferences, select "Allow duplicates" or "Do not export duplicates" if you have duplicates in your folder.
4. Click on Finish (it will take some time after you click finish)
For exporting contacts, repeat the same steps above except, in step 2, when selecting Calendar, instead select Contacts as shown here.
At the end of all of the above steps, you will have two PST files:
1. PST with Calendar
2. PST with Contacts