have also run a check db which failed with this error:

A database snapshot cannot be created because it failed to start. [SQLSTATE 42000] (Error 1823) The database snapshot for online checks could not be created. Either the reason is given in a previous error or one of the underlying volumes does not support sparse files or alternate streams. Attempting to get exclusive access to run checks offline. [SQLSTATE 42000] (Error 7928) The database could not be exclusively locked to perform the operation. [SQLSTATE 42000] (Error 5030) Check statement aborted. The database could not be checked as a database snapshot could not be created and the database or table could not be locked. See Books Online for details of when this behavior is expected and what workarounds exist. Also see previous errors for more details. [SQLSTATE 42000] (Error 7926). The step failed.