What can cause my C drive to bloat 10-20 Gigs in a few minutes?

I try to keep my boot SSD HD lean. I have Win updates disabled until I want to update. I have as many things as I can find to prevent any kind of tampering with my computer by MS or anyone. I am connected to the internet, since I need to be.


I make a lot of image files of my C drive. Lately I've noticed unusual sizes of my images that are unexplained. For instance I reverted to a 29 Gig image, did some minor changes and made a new image file that was 43 gigs. I reinstalled Acronis and did some more images which are even larger 55 gigs.


So I reverted back to the 29 gig image and saw that my C drive was 50 gigs. The reason it's larger than the image is because when I make an image file it is compressed., so it's about half the size (similar to a zip file)


I rebooted and all of a sudden my C drive was 59 gigs. I didn't make any changes, just rebooted. How can my C drive bloat like that?


If I can answer this question, I may be able to find out why I'm getting considerably larger image files. Equally strange is a few hours later with the computer inactive it reduced back down to 50 gigs. My page file is about 2.5 gigs. I'm baffled. Any ideas?

I downloaded Treesize, but haven't installed it yet. I have another simple program that does tell me how big folders are. Is this what Treesize does or does Treesize do more than this?

Can Treesize let me know what files and folders swell up in size in the short period of time.? Or do I have to just do this manually by lookign at all the folders?

I'm still trying to figure out what's causing this bloating. I had my HD today down to 50.5, but now it's up to 76 gigs again. I'm currently running Backblaze which is an online backup program to the cloud I started in January. When it copies large files it breaks them up into tiny 10 MG pieces and once it has all the pieces, puts it together in my online storage space as one file.

If anyone has experienced anything like this bloating, please chime in so I can find out the cause. I did find that Win 10 turned my Win updates back on to Manual (triggered). I then disabled it again.

I don't want anything in the background increasing he size of my boot drive without me knowing it or how to combat it right before burning a new image file

GerryPeters said:

I have another simple program that does tell me how big folders are.

I noted that you said you're still trying to figure out what's causing your storage issue, but I'd be curious about what information the program you mentioned has yielded, if anything.

As far as your current standpoint, I want to say I could only speculate about what may be causing your issue. If you were able to perhaps use your own software or, possibly even better, provide a screenshot with the Treesize software @thomaseg1 recommended, it would serve as some initial insight for those attempting to help you.

As for speculation, the first things that came to mind were ... perhaps a combination of your system's pagefile management, Windows Update, and amount of space reserved for Restore Points. Although a less likely culprit, yet still a potential cause... malware, specifically of a worm variant.

Since you've already downloaded the Treesize software, perhaps see if it sheds any light on the issue, but a thought I had was to use CCleaner (also free... in a trial version). It is specifically designed to clean and free up space on your hard drive, and would scan your system for various elements that can be removed to free up space. And actually, restore points are one of the aspects it scans, as well as old Windows Update data, etc.

P.S. I apologize, but as I was describing CCleaner, I happened to remember... a rather tricky behavior Microsoft decided to pull on those who upgraded from Windows 7. So in lieu of that, did you happen to personally upgrade from Windows 7, or was the system pre-installed with the Windows 10 OS?

Either way, try going to your C: drive, right click it, go to properties, find Disk Cleanup about middle ways on the dialog box, then once the next window pops up, disregard the regular, typical cleanup and find the Clean System Files option with the User Account Control shield (yellow and blue) that prompts you for Administrative privileges, and wait for the 'hidden' cleanup checkboxes that are not normally shown.

Sometimes, you'll find a checkbox next to 'Old Windows Installation' or something to that affect... which can be 20-30GB or more on its own. This is actually the entire image of your OLD Windows 7 installation that Microsoft decides to save just in case you decide you want to roll back, though I'm not entirely sure that's even an option anymore.

Regardless, I happened to think of it, and wanted to be thorough in finding a possible cause for your issue. Hope this helps. Good luck.

Here's the TreeeSize screenshot. Last night before going to bed my C drive was 76.7 gigs. As usual I left Backblaze backing up all night. This morning C was 69.0, now 2 hours later it's 68.0. TreeSize shows Backblaze at 19.7 gigs. So clearly this solves the mystery.

TreeSize is amazing, far better than the other folder size program I have. I can now clearly see that Backblaze is the culprit. In the last folder there are 1805 files and 17.6 gigs. You can see each file is 10 MG, because Backblaze cuts up each file in pieces since if the computer is shutdown, you don't want to lose hours and hours of work on partially copying a file, whereas it's ok to lose a 10 MG file.

I just heard from Backblaze tech support and she told me how I can change the temp folder to a different drive. I just did, so this really solves the problem of fluctuating C drive size.

Thank you Trexx for your info. I love CCleaner and use it usually right before making an image. I just Run it without checking the default settings. In CCleaner I see under Tools/restore points and it's blank. I never use restore points, since I prefer image files instead. So I may have disabled restore points a long time ago. If not I'd like to, so I don't have other extra data on my C drive

I now have Windows Update disabled, sometimes it gets turned back on. I upgraded from Windows 8 to Win 10, a long time ago.

If I find my C drive has gotten too large I use Disk Cleanup Clean/ System Files to see if there's anything to delete, especially like old Windows Update data or an old Windows install. That was 18 Gigs after the Fall Creator's update. Since I use image files I have no use few those files.

GerryPeters said:

TreeSize is amazing, far better than the other folder size program I have.....

Yes, it is. When run as administrator it can see into folders that even an administrator cannot look at. The hidden 'System Volume Information' folder for example, where your restore points are stored.