There is a bug in Apple's disk image creation software. We have a fix for that issue. We will move the fix back to the 2013 version when able. Hopefully that will fix the issue you are experiencing. In the meantime, you can make a backup by duplicating your company file and dragging it to wherever you wish to store it.  To find the location of your company file hit command-1 while in QuickBooks the click on the folder "track" that appears on the bottom to open the enclosing folder.