The Disk Cleanup utility (cleanmgr.exe) is installed by default on the GUI editions of Windows Server 2016/2019 (Desktop Experience). However, in previous versions of Windows Server (2012 R2/2012/2008 R2), the cleanmgr.exe tool is missing.
To clean the system disk from unneeded files on Windows Server 2016 using the Disk Cleanup utility, you need to open the disk properties in File Explorer and click the Disk Cleanup button. You can also type the “ disk cleanup” or cleanmgr.exe