Is your system drive or the drive where Windows 10 is installed running low on disk space after installing the recently released Anniversary Update for Windows 10? Do you want to regain the lost disk space? In this article, we will see how to free up disk space after installing the Anniversary Update for Windows 10. When you upgrade your Windows 10 to Anniversary Update (version 1607), Windows 10 automatically creates a backup of your previous build of Windows 10 to a folder called Windows.old so that users can uninstall Windows 10 Anniversary Update and go back to the previous build if required. In this guide, we are going to delete these files required to go back to the previous build of Windows 10. Please don’t use this method to free up disk space if you plan to go back to the previous build of Windows 10 for any reason. Regain disk space after installing Windows 10 Anniversary Update Refer to the given below instructions to free up a significant amount of disk space after installing the Windows 10 Anniversary Update. Method 1 of 2 Step 1: Open the Settings app by clicking on its icon on the left side of the Start menu. Or simply use the Windows logo + I hotkey. Step 2: Navigate to System > Storage. Step 3: Click on the drive where Windows 10 is installed. For your convenience, the Settings app displays the Windows logo on the drive Windows 10 is installed. Step 4: When you are at the Storage usage page, scroll down to see Temporary files. As you can see in the picture below, the Settings app displays space used by Temporary files, including Windows.old folder. Click on Temporary files. Step 5: Finally, select the Previous version of the Windows option and then click Remove files to free up GBs of disk space. Additionally, you can also select Temporary files and then click Remove files to delete temporary files safely. Method 2 of 2 This is the classic method of deleting previous Windows installation files to regain lost disk space. Step 1: Open up This PC. Perform a right-click on the drive where Windows 10 OS is installed and click Properties. Step 2: Under the General tab, click the Disk Cleanup button. And if the Disk Cleanup button is not showing up, please refer to our fix to disk the cleanup button missing from the drive properties guide to restore the button. Step 3: When you see the Disk Cleanup dialog box, click the Clean up system files button. Step 4: Finally, under Files to delete section, select Previous Windows installation(s) and also select Temporary Windows installation files, and then click OK button to remove files from previous Windows 10 build to free up disk space. To recover more drive space, refer to our 16 ways to free up drive space in Windows 10 article.