Azure VM - You are running out of disk space on C:

Our Azure VM instance run out of disk space. It has only 30GB C: disk and after few months it's barely sufficient to hold Windows 2012 with basic applications.



There were two solutions:

1. Enlarge disk C: on Azure VM... the complicated way (stop VM, dismount, enlarge the VHD, mount, recreate the VM etc...)
2. Compress some unused stuff on disk... the easy way 

So I've chosen the easy way. I installed Folder Size 64bit, the expansion for Windows Explorer, and found that one of the biggest folders is "%WINDIR%\WinSxS". It shouldn't be deleted as there are some useful installation files, but can be compressed. So I did it as described here: http://dandar3.blogspot.com/2013/01/how-to-ntfs-compress-windows-winsxs.html.

Compression took 30 minutes. After that I've 3,90GB free space on C: drive,  enough for few next months.