Can windows 10 be installed on EXTERNAL Hdd, without erasing existing data ?

Not creating bootable drive, but running windows from it.

This is only a temporary solution to test the system.

Is it possible to install Windows 10 on a seperate partition on external hdd ?

NOTE :- THERE IS LOTS OF DATA ON IT ( BUT ENOUGH FREE SPACE FOR WINDOWS ).

SO DONT WANT THE DATA TO BE ERASED.

Thank you.