I had a server that had the "Microsoft Exchange Writer" missing.
When typing the command vssadmin (C:\>vssadmin list writers) from a command prompt all the VSS (Volume Shadow Copy) writers would come up besides the "Microsoft Exchange Writer".
This is what the Microsoft Exchange Writer looks like should it come up:
If it does not come up in the list... to enable it navigate to the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
Modify the "Disable Exchange Writer" registry key to a value of 0
After this restart the "Exchange Information Store" service
"vssadmin list writers" should now display the writer correctly
Check the Technet article for more information: http://technet.microsoft.com/en-us/library/bb795725.aspx
