I was able to free some space on the drive by using "Disk Clean Up" and removing restore points. Still a mismatch between what I SEE and what it is reporting. I figure I should be able to gain about 180GB! That's alot of space...
Have you tried to view hidden files?
Yes, I am currently showing hidden files. See photo HERE.
Start/Run...type diskmgmt.msc and hit Enter.
Post a screenshot so that we can see.
See photo HERE.
Check your file system with command chkdsk /f
Here is the result:
Microsoft Windows [Version 6.1.7601]
Copyright © 2009 Microsoft Corporation. All rights reserved.
C:\Windows\system32>chkdsk e: /f
The type of the file system is NTFS.
Volume label is Backup.
CHKDSK is verifying files (stage 1 of 3)...
4864 file records processed.
File verification completed.
0 large file records processed.
0 bad file records processed.
0 EA records processed.
0 reparse records processed.
CHKDSK is verifying indexes (stage 2 of 3)...
5678 index entries processed.
Index verification completed.
0 unindexed files scanned.
0 unindexed files recovered.
CHKDSK is verifying security descriptors (stage 3 of 3)...
4864 file SDs/SIDs processed.
Security descriptor verification completed.
408 data files processed.
CHKDSK is verifying Usn Journal...
8485032 USN bytes processed.
Usn Journal verification completed.
Windows has checked the file system and found no problems.
488384000 KB total disk space.
340221136 KB in 4410 files.
2236 KB in 409 indexes.
0 KB in bad sectors.
94428 KB in use by the system.
65536 KB occupied by the log file.
148066200 KB available on disk.
4096 bytes in each allocation unit.
122096000 total allocation units on disk.
37016550 allocation units available on disk.