How to do the installation of win10 actually used 30G?

1, win10 itself takes up the root disk space is not large, below 20G, but the upgrade will cause the previous preview version of the residue, especially the recent versions have changed a lot, basically a new installation, so will automatically generate windows.old directory In order to retreat.

2, this directory is also about 10G, forcibly use the right button to delete, will report the system permissions are insufficient, can not be deleted, then how to delete it?

3, in my computer, Right click on the drive letter of the directory, such as Xiaobian is on the C drive, select the bottom line in the pop-up menu <Properties>

4, select the <General> tab in the pop-up menu. Then select the location of the following image <Disk Cleanup>

5, the system will automatically scan and collect the space that can be cleared, but the system does not clear the system file by default, you need to select <clean in the pop-up menu System file>, as shown in the red circle below

6, the system will calculate the space again, this time will calculate the old system file, select the <previously installed windows> check box, there is 11G If you want to clean up again, you can also select the <temporary windows installation file>, which is also close to 2G, and then click OK.

7, the system will show that the file on the C drive is being cleaned up, so that after cleaning, the root disk can get nearly 13G more space, which is really slim.