The File Explorer by default opens to Quick Access (replaces "Favorites" in previous Windows versions) by default. Quick Access is a section where you can place shortcuts to your favorite folders. Quick Access also displays recently viewed files and frequently used folders. If you want File Explorer to open to "This PC" by default, you can do so using Folder Options.
Start File Explorer, and click the File menu.
Click Folder and search options
In the Folder Options dialog that opens, select This PC in the Open File Explorer to: drop down box, and click OK.
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Ramesh Srinivasan founded Winhelponline.com back in 2005. He is passionate about Microsoft technologies and has a vast experience in the ITeS industry — delivering support for Microsoft's consumer products. He has been a Microsoft MVP [2003 to 2012] who contributes to various Windows support forums.