Hi, Thanks for your valuable comments, including this: "What you describe with keeping a backup "up-to-date" is IMHO (in my humble opinion) not a backup but a synchronisation. That is different. " So, is there some additional functionality in 'backup' which is not inherently present as a result of synchronisation? Synchronisation, per se, is not my objective: that has to be a resilient disaster recovery process. Much of my data, especially photos I took in the 1950s onwards, if lost, is unrecoverable. FreeFileSync does make robust copies for me, which I regard as backups, because they are on separate media, on separate computers and in separate locations. It is just a very time consuming process, which BIT addresses. Synchronisation - for example by using FreeFileSync - is just a by-product. I don't really like it because of, for example, Apple's implementation of synchronisation of my low resolution image portfolio: I would like to keep my 'master' collection on one of my desktop PCs, copied, for convenience, to iCloud and a subset of this collection on my iPhone. I can't do that: if I delete an image from my iPhone (to conserve memory) it is gone too from iCloud, and my desktop if I allow synchronisation to happen. That's Apple telling me which images I can have and where. This infuriates me.