I keep getting this message when I try to Verify Disk: "Checking Extents Overflow file. Checking Catalog file. Illegal name Illegal name Checking multi-linked files. Checking Catalog hierarchy. Checking Extended Attributes file. Checking volume bitmap. Checking volume information. The volume Macintosh HD needs to be repaired. Error: The underlying task reported failure on exit 1 HFS volume checked Volume needs repair " It won't let me repair. Can you tell me what this all means?