Read https://www.cnet.com/how-to/how-to-delete-the-windows-old-folder-from-windows-10/
I just purchased and setup an ACEPC AK1 Mini PC Windows 10 Intel Celeron J3455 Quad Core 4GB RAM 32GB eMMC. As I was browsing through drive C to look for files/folders I don't need to give more usable space, I noticed a folder "windows.old". Once in a while I would get a notification that I'm running low on storage and to delete old version of windows. Is the "windows.old" folder safe to delete?

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