Hard drive shows full with almost nothing installed on it!

I installed the tool shown above per an MS blog that MS recommended.  How can the HD be 155GB when it's only 128GB?  Why does it think it's 155GB?  Has anyone ever seen this issue before where the actual HD capacity is much smaller than it thinks it is?

Every storage device, regardless if it's a hard drive, SSD, or USB flash memory, always reports the drive as having slightly less capacity. This is because when formatted, the file system reserves a small portion of the drive's rated capacity, which reduces the actual capacity that can be used for storage. Also, various recovery and service partitions present on your computer will further reduce the rated capacity of the C: drive.

As for the storage drive in your computer, 128 GB is considered small for today's applications, considering that a fresh install of Windows can use up to 20 GB. For basic tasks and internet usage, 128 GB is usually enough. However, installing additional programs, as well as storing personal media files, will quickly use up whatever free space is left.

Using Disk Cleanup as well as CCleaner can unclutter the drive by removing temporary and unneeded system files. However, most of these files will re-populate over time, so it is important to run these programs occasionally.

Also, open the Control Panel and open SupportAssist OS Recovery. Click on the settings tab and turn off system repair. System repair is like System Restore in Windows, and it will store snapshots of system related files that can be used to restore your computer back to a working state if there is a problem. System repair can use up to 20-25 GB of space when enabled, so if you don't need or plan on using System repair, you can disable it. Once disabled, all snapshots will be deleted.

The long term solution would be to upgrade the SSD inside the computer with one of a larger capacity, then reinstall Windows or clone the contents of the existing drive over to the new one. I recommend upgrading to at least a 500 GB SSD, which should be more than enough, unless you're planning on saving lots of large files in the future, then I would go higher. Assuming that your current SSD is a M.2 form factor, replace it with a 2280 NVMe SSD to maintain performance.

@Kflash08​ 

your 1st paragraph...yes, I understand that.  That's why Dell sold us the SSD as having 128GB when on the C: drive it shows only 116GB.  I already looked to see how much of the 128GB space is allocated for other things, and it's negligible.  This still doesn't explain why the TreeSize app shows the SSD being 155 GB.

2nd paragraph...128GB should be more than enough to accommodate an upgrade from Win 10 to 11.  There are no user profiles on the SSD other than a local and domain admin profile, which has almost nothing in it either.

3rd paragraph...as I mentioned, I already ran every possible type of cleanup tool, including Storage Sense, completely deleted the Windows\temp folder, and countless other things.  I also deleted all apps except the most basic ones like antivirus and Dell Command Update.

4th paragraph...I had already run the Dell Support Assistant tools.  Didn't help.  The SSD has no system restore points; I had already looked at that too, and system restore is turned off.  I also already ran sfc /scannow, chkdsk repair, and DISM cleanup and restorehealth tools.  Nothing helped.  After I did all this, I uninstalled Support Assist to reduce what is on the SSD.

5th paragraph...no data files are being stored on this SSD.  I already completely deleted the 1 user profile that was on there and it hardly used any space anyway because the user is rarely in the office and had only a handful of files.  But like I said, I already deleted that profile anyway.

If a 128GB SSD is "too small," for an upgrade to Win 11, why would Dell sell us an SSD of that size?  Surely they must have known that Msoft would be updating Win 10 to a newer OS soon.

This happened once before to another Dell PC of this same model and SSD size.  That other PC was still under warranty (this one is not), so I called Dell Tech Support; they couldn't figure out why the SSD had filled up either without us having even upgraded it to Win 11, so they sent me another 128GB SSD as a replacement, which is still in use on that other PC, but we left the replacement SSD on Win 10, not having upgraded to Win 11.

I also checked the specs for the PC on Dell's site and confirmed that it's an SSD.  I believe that Dell sold us a bad batch of SSDs in the micro 3080 PCs.  It's not the 1st time that Dell sold us PCs with bad drives.  I'm surprised that no one else has reported having an issue with these 128GB SSDs.

@SaltyPines​

If a 128GB SSD is "too small," for an upgrade to Win 11, why would Dell sell us an SSD of that size?  Surely they must have known that Msoft would be updating Win 10 to a newer OS soon.

Cost. SSDs cost more per gigabyte compared to a hard drive. 128 GB was the smallest SSD that Dell offered with their systems at the time, and it allowed the customer to benefit from the performance improvement while keeping the price of the system down. On the other hand, they could have offered a 1 TB hard drive instead for around the same price as the 128 GB SSD, which would have provided much more space, but at the cost of performance.

SSDs since then have drastically fallen in price, and pretty much every new system sold today comes with a decently sized SSD. A 500 GB NVMe SSD can be bought for around 50 dollars now, and 1 TB for about 70.

I don't know why this forum removes any picture files I try to post.  I click the image icon from this toolbar, click browse files, find the image, click the Add button, it shows the image in the post, but as soon as I click Post, it removes the images.