Excessive Storage?

Followed other threads but found no quick fix.
Using various methods to look at my Win10 Pro C:\ storage. No old install or associated files, with an empty bin and a single restore point:

Explorer Local Disk (C:) - 173GB free of 237GB

Disk Management
Recovery Partition - 450MB
System Rreserved - 350MB
C: - 237.69GB

System - Storage - This PC (C:)
64.5GB used out of 238GB
System & Reserved 48.3GB with split System 47GB, Virtual Memory 1.01GB, 287MB System Restore of 4.75GB allocated.
Apps & Games - 8.89GB
Other - 4.08GB the largest part being 3.12 GB C:\ESD
Documents - 3.88GB
Pictures - 830MB
(total others 90.62MB)

In agreement that usage on the C: partition is about 64GB of 237GB. Using various 3rd party utilities (WinDIRStat etc) C:\ is more like 43GB e.g. TreeSize:

42.7GB C:\ with
15.6GB Windows
11.6GB ProgramData
6.2GB Users
3.1GB ESD
1.8GB Program Files (x86)
1.3GB Program Files
1.0GB 31 Files
+ 9 files all less than 1MB

These on an SSD with 4096 bytes/cluster NTFS.

Win10 has 64GB used in C:\ but other utilities say 43GB on C\: and I am trying to explain the 21GB difference. Is it storage that I could partially recover? With System at around 47GB but only 15.6GB for Windows (Explorer says 14GB) then there could be an issue in the 'System' section. Could it be that filesize vs. filesize on disk could explain the difference?
*this is a recent Windows install chkdsk, scannow and other tools have been run without flagging issues.

Thanks Dave

axe0 said:

Please follow this tutorial and post a screenshot of your disk management.
Disk Management - How to Post a Screenshot of - Windows 10 Forums

As requested but not that informative.

Settings - Storage vs TreeSize run as Admin.

axe0 said:

Mine isn't very accurate either, it is a few GB out of range of what Windows tells me.

Have you tried to reinstall the programs? I would suggest to remove them using Revo Uninstaller.

More than a few GB out. Do I believe Explorer or a 3rd party utility? On my laptop a similar software installation is C: - 33GB used space. The desktop has Garmin Basecamp with a Europe map adding another 10GB so roughly 10GB + 33GB on the equivalent laptop but that would mean Explorer at around 64GB is where the problem lies?

Maybe it is Windows that needs reinstalled rather than the programs - I am trying to avoid reinstalls of anything.

In the WinDirStat menu/options check Show Unknown and see if any space is used for Unknown.

axe0 said:

I don't know where the problem lies nor which one is correct.
If you really think that Windows needs to be reinstalled then a good way is using an in-place upgrade
Repair Install Windows 10 with an In-place Upgrade - Windows 10 Forums

This thread follows on from an in-place reinstall aimed at fixing the storage issue. A clean install may have been the better option. I have current data backups but before formatting the storage would like to be sure that future issues can be avoided.