I've checked this with the Cloud team and they have confirmed it is not possble to put BT Cloud on another drive.
The BT Cloud Sync folder (key part of the programme) is always personal so needs to sit in the user’s home directory – on Windows this is always on the system disk which is usually C: drive. The installation folder for BT Cloud also automatically resides under the user profile on the hard drive (C:\Users\[USERNAME]\AppData\Local\F-Secure\BT Cloud\Application), so unfortunately it is not possible to put BT Cloud on another drive.
Hi. Whilst I appreciate a response to this has been made last year, I've recently installed bt cloud because my dropbox subscription has expired. Dropbox allows you to install the sync folder to any drive you specify (if you have another drive connected or even external storage). I find that in this day n age where connectivity is using multiple ways to store, this option of not being able to locate the sync folder to another drive is limiting the experience of the user.
Will BT consider allowing this sync folder functionality to be moved to a location the user prefers in the future? if you can imagine the frustration of syncing to the c-drive, then moving the contents to your external storage (where you want it to sync to in the first place) could be offputting.