does Google's Backup&Sync use drive D:? D is filled with 'Other' stuff: 454 MB

[TAB42]

Suddenly I am getting messages 'You are running out of disk space Drive D'. I check:
LocalDisk D: 504 MB; Storage usage: 471 MB used, 32.9 MB free
Other: 454 MB; System&reserved: 16.1 MB; Documents:…

What is this 'other' storage? Win10 says:

LocalDisk D: properties
>Events
2018-04-11 21:23:48 Device migrated Device SCSI...was migrated
2018-04-11 21:23:48 Device configured (disk inf)
2018-04-11 21:23:49 Device started

2018-04-11 is the date I started Google's Backup&Sync.
Did Google 'migrate' my disk, and fill it with junk?

 

[hang-the-9]

It would not have unless you told it sync D with your online files and it's trying to do that. Check your settings.