msg 7928, Level 16, State 1, Line 3
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.
Msg 8921, Level 16, State 3, Line 3
Check terminated. A failure was detected while collecting facts. Possibly tempdb out of space or a system table is inconsistent. Check previous errors.
Read on to see what this means, as well as what it means for you.