If your computer is upgraded from Win 7 or Win 8 to Win 10, and the space on drive C is getting smaller and smaller, it is suggested to delete the file Windows.old, which can free up a lot of space on drive C..

Windows.old file is the backup file of Win7/8 system automatically created when Win7/Win8 system upgrades Win 10, which is convenient for users to roll back to the old system in the future. If you don't plan to reduce the price to Win7/8 system after upgrading Win 10, you can delete this Windows.old file.

The file size of Windows.old is generally above 5GB, and some even reach 10GB. Deleting this file will undoubtedly release the space of drive C to a great extent.

Deleting the windows.old file is very simple, just go to Disk Cleanup and delete it. The specific steps are as follows:

1, first enter this Win 10 computer;

2. Right-click the C disk of the system, and then click Open "Properties";

3. Click "Disk Cleaning" under the Disk General tab, and continue to click "Clean System Files";

4. Finally, check "Previous Windows Installation", and then click "OK" at the bottom to start cleaning.

2. Delete Win 10 hibernation file.

Hibernation is a power saving mode. During hibernation, the system saves the data in the memory in the hard disk, so the CPU also stops working. When you use it again, you need to press the on/off key, and the machine will return to the state when you were asleep, without having to perform the complicated process of restarting Windows.

In real life, most users rarely use this function, not to mention that the volume of hibernation file is almost the largest in Windows system, and deleting it can definitely get twice the result with half the effort.

How to delete Hibernate files? Methods of compressing and clearing Hibernate files.

1. First, use Win+R shortcut key to open the run dialog box, then enter cmd, and click OK at the bottom to open the command operation box, as shown in the figure below.

Then in the CMD command box, enter or copy and paste the following command:

Powercfg dormancy size XX

Note: The "XX" at the end of the above command indicates the percentage value, ranging from 40 to 100. Recommendation 40 or 80. Users can enter a value less than 40 to keep the hibernation file size at 40% of the system memory size, as shown in the following figure.

Finally, let's take a look at the changes of hibernation file size after compression rates of 80 and 40, as shown in the figure.

80% and 40&; Hibernate file size after compression command

By compressing the hibernation file, the system space can also be effectively released, which can alleviate the embarrassment of insufficient C disk.