Table Corrupt: Extent id %ld on allocation pg# %ld has objid %ld and used bit on, but reference bit off.
If an allocation structure or extent is not linked to the other extents for the object referenced by objid but references a page that is linked in the object's page chain, DBCC CHECKALLOC will trigger this error. Each occurrence of this error can represent a loss of up to 8 pages on disk (16K). There is no data loss because these pages have not been used, but the pages cannot be used until the error is corrected. This error can result in various run-time failures and should be corrected; however, if no other errors are occurring, you can wait to correct the problem until non-peak hours.
Note Occasionally DBCC CHECKALLOC reports this error when no real error condition exists. Run DBCC CHECKALLOC in single-user mode if you suspect the 2546 error message is incorrect.
Restore the database from a known clean backup. If the problem persists, contact your primary support provider. Have the output from the appropriate DBCC statements available for review.