Hi RK,
Welcome to Microsoft Q&A forum. I'm happy to help.
The 190 MB portion likely consists of temporary files currently in use by applications or the Windows system, which is why "Cleanup System Files" cannot remove them. You may be able to delete some of these files by booting into Safe Mode and then running "Cleanup System Files".
The extra 5 GB of disk space may be related to the Windows Update cache. You can check two locations: C:\Windows\SoftwareDistribution and C:\Windows\System32\catroot2. If you recently upgraded Windows, there might be a C:\Windows.old folder. You also can manually clean up Recycle Bin by running this command in Command Prompt as Administrator: rmdir /s /q C:\$Recycle.bin
Not only the Windows system and Microsoft Edge, but most applications create temporary files to store data. Typically, these files are managed and deleted automatically; however, sometimes they are not properly cleaned up and remain on the system. My advice is that you do not need — and should not — perform cleanup tasks frequently unless your free space is low. Modern systems use SSDs for "C" drive, which have a TBW (Total Bytes Written) limit. Unnecessary frequent cleanups increase the total data written and can cause your SSD to wear out faster.
The "C" drive space is filling up not only by temporary files but also by files created for each application’s purpose. While temporary files are easy to delete, components like indexing are harder to optimize or remove. Over time, the indexing database can grow significantly as you use Windows.
For convenience, my suggestion is ignoring the temporary files. One day, may be next few years, when you realize that your system needs a smoother experience, then you may back up necessary data and perform a clean install.
I hope that above information is helpful to you.
If you have further questions, please feel free to let me know.
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