Does Windows 10 S installer delete files on other drives?

Check this article. Microsoft described how to install Windows 10 in S mode in existing Installation. I also want S mode of Windows, so I also want to do that. Everything is fine, but I am worried that, does the installer delete anything out of C drive? Well I backed up everything of C:, but I have a lot of data in D: so I am worried that if it gets deleted? Have anyone tried this? Did it deleted any other drives?? Thanks!

All Windows installers only touch the system drive for software installation.

The installers don't touch other disks, unless, for example, a specialized partition is required for recovery. But even then it will only reduce the size of some existing partition to create the new partition, and will not delete existing partitions.

An exception for Windows S might occur when non-Microsoft software is installed on a non-system disk. However, according to your link, non-Microsoft apps will simply not work. The article does not mention the uninstallation of such applications.

Before doing the installation, I suggest taking a disk-image backup of the current system disk (not only the partition), in case you will find that Windows 10 S is too limited and wish to return to your previous state.