CHKDSK issues on my external drive

Microsoft Windows [Version 10.0.17763.529]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>chkdsk N:
The type of the file system is NTFS.
Volume label is 6TBDATA.

WARNING!  /F parameter not specified.
Running CHKDSK in read-only mode.

Stage 1: Examining basic file system structure ...
  2390272 file records processed.
File verification completed.
  111731 large file records processed.
  0 bad file records processed.

Stage 2: Examining file name linkage ...
  80057 reparse records processed.
  2667838 index entries processed.
Index verification completed.
  0 unindexed files scanned.
  0 unindexed files recovered to lost and found.
  80057 reparse records processed.

Stage 3: Examining security descriptors ...
Security descriptor verification completed.
  138784 data files processed.
CHKDSK is verifying Usn Journal...
  39533848 USN bytes processed.
Usn Journal verification completed.
The master file table's (MFT) BITMAP attribute is incorrect.
Windows has checked the file system and found problems.
Please run chkdsk /scan to find the problems and queue them for repair.

   5723035 MB total disk space.
   5714784 MB in 1922694 files.
    569608 KB in 138785 indexes.
         0 KB in bad sectors.
   2700743 KB in use by the system.
     65536 KB occupied by the log file.
   5179252 KB available on disk.

      4096 bytes in each allocation unit.
1465097215 total allocation units on disk.
   1294813 allocation units available on disk.

C:\WINDOWS\system32>chkdsk N: /scan
The type of the file system is NTFS.
Volume label is 6TBDATA.

Stage 1: Examining basic file system structure ...
  2390272 file records processed.
File verification completed.
  111715 large file records processed.
  0 bad file records processed.

Stage 2: Examining file name linkage ...
  80058 reparse records processed.
  2667838 index entries processed.
Index verification completed.
  0 unindexed files scanned.
  0 unindexed files recovered to lost and found.
  80058 reparse records processed.

Stage 3: Examining security descriptors ...
Security descriptor verification completed.
  138784 data files processed.
CHKDSK is verifying Usn Journal...
  39549040 USN bytes processed.
Usn Journal verification completed.

Windows has scanned the file system and found no problems.
No further action is required.

   5723035 MB total disk space.
   5714786 MB in 1922700 files.
    569608 KB in 138785 indexes.
         0 KB in bad sectors.
   2700743 KB in use by the system.
     65536 KB occupied by the log file.
   5177460 KB available on disk.

      4096 bytes in each allocation unit.
1465097215 total allocation units on disk.
   1294365 allocation units available on disk.