Originally Posted by skorvek
I can confirm this bug still exists in 1.10.4 Revision: 174315.
The workaround I found is to create a new folder in my home directory called "OmniFocus" (no spaces, not "OmniFocus Backups") and then choose that directory as the backup location with the file chooser. That sets the correct location in the preference pane, and backups do indeed go there. I then just dumped the old backup files into the new folder and deleted the old ones.
When I initially tried to move the folder, I too started seeing backups every minute in my home folder, but that behavior stopped when I performed the above procedure.
It seems that the path isn't properly escaped to allow long folder names with spaces.
OmniFocus has been backing up to a folder "~/Documents/foo bar" for me all day without complaint. I clicked the "Browse" button, navigated to where I wanted my test backup folder, clicked the "New Folder" button, created my folder, then clicked the "Open" button to select it. After that, the backups went there without any further action on my part. Anticipating the next possible objection, I also successfully tried it with a considerably longer pathname with many components separated by spaces.
If you just tried editing the text field showing where the backups go, you probably won't be successful.