Hi,
I suppose I should join a Linux form to ask this but I'll probably get the answer here

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I'm planning to install Linux on a 3TB USB drive to act as a portable/backup machine. I would also like to use it to backup the user files from my desktop machine. OS in both cases in Linux Mint. I generally make 4 partitions. One is swap space and the others are mounted at /boot/efi, /, and /home. I make /home/User_Files/ for all our docs, photos etc.
My question is this: if I do this can I then plug the USB drive into my desktop machine when it is running (ie not booted from the USB), mount /home/User_Files to eg /mnt/backupdrive/ and then copy files onto the USB drive? Can I do this without corrupting the file system and have the files visible to the OS on the usb drive when I boot from it? I believe it should work but I'd like to be sure before I start.
Thanks for any advice.