Any Online backup solution compatible with open project?

I believe the answer is no but I wanted to check.

Could you clarify a bit on what you mean by open project? If you follow the rules you can edit off of the Dropbox folder. Dropbox is a fantastic service, and free so long as you don’t need to store tons of data online.

If you mean something more along the lines of having a project open on two computers (say, two authors working on the same book project) then no, that would require some fundamental architecture changes at the core of Scrivener, and no service will circumvent that.

I mean that if I have a Scrivener project that is open all the time are there any services that will still be able to create a backup correctly.

I know these services don’t work correctly with an open project
Time Machine

Ah ha, I get what you mean now. Not really, because the problem isn’t Time Machine or any other backup that runs periodically in the background, it’s that Scrivener has the project open and set up for editing. These and any other tools can only access what is actually on the disk at any given time, and what is on the disk is an open project.

What I recommend doing is closing your projects at the end of the day and using the Time Machine button in the status bar to “Back Up Now”. This last backup of the day is the one that will get saved. So run that, and when it’s done, shut down for the night. So in other words today you have say 6 backups for every hour you were on the computer. But tomorrow Time Machine will only save 1 of those to represent all of March 9 2011, the 6th backup. So make the 6th one that you control, and all the old historic backups will be assuredly complete.

The good news is that any backups that Scrivener makes will be un-opened (and probably even zip archived). So if you tend to keep Scrivener open for long periods of time, set up your backups to trigger when you manually save. Now just hit Cmd-S whenever you feel like you need to back up your work. This not only gives you immediate access backups, it backs up along with everything else in Time Machine. That means you have multiple redundancies for the past 30 days: the main project, and each individual interval backup Scrivener created as a zip file. March 9 now not only has the master .scriv file, but five (by default) additional copies made during the day—whenever you felt a substantial chunk of work had been done. That is a very fine level of restoration power at your disposal.

So option two: if closing the project every night and doing a manual Time Machine trawl seems like too much work, just take the above paragraph and remember to hit Cmd-S at the end of the day. This way at the very least you’ll have a daily entry with an open copy of the project, and one backup that is identical to the open copy. Any other Cmd-S backups you make during the day are gravy.

That’s exactly what I (And loads of others do). Just do a cmd-s every once in a while and point your backups at a dropbox folder. (I also have mind backed up by Mozy)