I feel stupid asking for help here, but it seems pretty weird. My Mac Pro is used mostly for my writing, and I keep a very full desktop - to get what I want quickly - I learn where to find it. I am on Mojave, and the files I produce are usually MS_Word files (docx). I recently noticed some files begining "Backup" that I did not put there. Example, I have a file of useful phone numbers that I consult occasionally. To spot it quickly I have colour-coded the icon using the tags at the foot of the Finder 'File' drop-down. One day I couldn't find it so searched through the docx lists and there it was, in the 'U' section, minus its colour tag. Odd, I thought. A day or so later I spot it, with colour tag - but it is no longer called Useful Numbers.docx - it is now called 'Backup of Useful Numbers.docx'. Looking again at the desktop list where the original was (beginning 'U') there it is - without the colour tag. I definitely did not create these 'backup' files - there are six or seven of them. If I had ever lost an original I could get it back in seconds using Time Machine. Can anyone help to explain this weirdness - am I bugged by a virus or trojan etc?