Last week, I noticed that my C: drive was running low on storage, with a little over 25GB of space left. First, I deleted a couple of large files from the Downloads folder, and it helped me reclaim 11GB. Even then, I barely had 36.5GB free on a 306GB volume. That got me wondering, what's taking up all that space? I don't install a lot of programs. It's usually a few that I regularly need. And even with Windows taking up close to 40GB, there should be more free storage. Additionally, I have an external SSD that I can transfer files to. But even for that, I have to figure out which files can be moved without affecting the system's stability. So, I spent the next few hours exploring built-in and third-party utilities, and by the end, I had over 120GB of free space on the system partition.

Use the built-in tools

They are good at quick cleaning

First, I opened Disk Cleanup, the built-in utility on Windows that lists non-critical, temporary files you can clear up instantly. With the default selection, it showed only 162MB as safe to delete. That was way too small, but after adding "Recycle Bin" to the list of files, I had over 9GB of storage to gain. I cleared that up immediately.

After that, I relaunched Disk Cleanup and chose the "Clean up system files" option. After adding "Delivery Optimization Files" and "Temporary Files", I managed to free up another 1.3GB of storage. That takes the total to around 10.5GB, only with Disk Cleanup. It may not be the same for everyone, but if you don't frequently delete temporary or leftover files, it should ideally be in a similar range. So, with just Disk Cleanup, I freed up a significant amount of space on the system partition. And it took less than 5 minutes.

Then I opened Storage Sense, another built-in tool that periodically checks for temporary files and removes them. For the most part, it performs the same operations as Disk Cleanup, but Storage Sense makes other recommendations that often prove helpful in reclaiming lost storage. Just open Settings, go to "System," then into "Storage," and allow it a minute to find out how the storage stacks up. Once done, click on "Cleanup recommendations" and check if anything suggested here can be removed. For me, there wasn't much to delete, but you should still check it. Sometimes, the recommendations here do come in handy.

By now, I had cleared most of the temporary, non-critical, and leftover files both for Windows and installed programs. Now, it was time to look for files and folders that would make the real difference.

Use a disk space analyzer

Best for deep system cleaning

Next up, I installed a nifty utility called WizTree. I had tried other similar tools in the past, but it had a lot of good reviews. So, I had to give it a shot. The setup was fairly simple. Upon launching the utility, I selected the C: drive from the dropdown menu, and within a few seconds, it came up with a detailed list of files and folders on the partition. By default, they were arranged by size, so it was easier for me to start. The biggest here was the "Users" folder, taking up over 100GB. It didn't come off as a surprise since my work required me to create multiple user accounts on Windows.

Then, I looked at the files within each user account on the system partition and deleted the ones I no longer needed. Also, I had a couple of duplicate VMs set up across profiles, which consumed massive storage. I removed those as well. By the time I was done with this cleanup, the free space increased to over 121.4GB. That was massive, and I hadn't yet touched anything that was even remotely critical, either for personal use or Windows, say hiberfil.sys, which took up close to 6GB. Disabling Windows Hibernation would have saved me another couple of GB.

Keep in mind that the results might not be the same for you. I had been pretty careless with files in the past, as evidenced by the amount of space I managed to free up. But WizTree is still worth a shot. There may be large files or games buried deep within the partition that you completely forgot about, and WizTree, or a similar tool, will help you quickly find and delete them. But don't remove anything from the Windows or Program Files directory unless you are absolutely certain what it does.

To give you an idea, I managed to free up 85GB on the system partition alone by deleting files and components that were either unnecessary or no longer required. If I transfer some to the external SSD, it might take that to 100GB, which is good enough for another year of careless use.

Windows handles storage well

But manual cleanup is still a necessity

The few hours that I spent freeing up storage on my Windows PC taught me that you shouldn't rely on a single tool, whether it's native to the OS or a third-party utility. Had I only used Disk Cleanup, it wouldn't have listed the VMs or personal files that I completely forgot about. Similarly, just WizTree wouldn't have helped me clear the update cache or temporary Windows files. In the end, it's the combination of the two that works best. And with features like Storage Sense, I can keep the PC free of clutter without regular manual intervention.