Guide to Resolve 100% Disk Usage Issue in Windows 10
It is quite common for the Windows 10 users to face this issue, and it can lead their device to hang and freeze from time to time, interrupting all the essential tasks for the day. Every device has its downside, and Windows 10 is one of them. So, the reason for why you see 100% disk storage could be the Windows 10 OS only, instead of all the space your photos, files, etc. are consuming. Its operating system slows down the desktop and affects HDD and SSD in the long run. There are a few bugs in the OS that prompts it to behave this way. 
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