Surely a company stuffed with billions of dollars is incapable of solving this either by enabling conflict handling or some ingenious methods.
All those billions of dollars are focused on making sure you can't replace your screen with an aftermarket part.
Indeed it's not like there aren't better solutions out there as shown by dropbox. Just keep both versions for a month and text you a warning.
But what is the fifth problem?
Because the two hardest problems in software are cache invalidation, naming things, off by one errors, and buffer overflows from a lack of array index enforcement.