*But Were Afraid to Ask
This is a part 1 of a 3 part blog series. Please see this for Part 2 and this for Part 3.
If you find the inner workings of Exchange data backups using Volume Shadown ...
Updated Feb 05, 2020
Version 3.0
Blog Post
@Amit, we have a VSS troubleshooting blog entry, although it's admittedly in need of updating for Exchange 2010:
Troubleshooting Exchange 2007 VSS Backups
http://blogs.technet.com/b/exchange/archive/2008/08/25/3406172.aspx
The big differences are in the Windows Server 2008 VSS infrastructure, along with the fact that BETEST now uses XML for the components files as opposed to text. Otherwise the concepts are the same.
An updated troubleshooting guide is still far off, so in the meantime you can try posting the errors you're seeing and circumstances of the issue in the forum:
Exchange Server 2010
http://social.technet.microsoft.com/Forums/en-US/exchange2010/threads
If there's no help there try MS Support.