Unsaved changes overwriting file on close


Is this expected behaviour? I couldn’t find any reference to unsaved changes behaviour in OG 7.

I was working on a file, saved what I was happy with, then experimented with a bunch of crap in the same file. I closed the file to discard the crap and work on something else. To my dismay, there was no “you have unsaved changes” dialog, but the unsaved changes were silently saved! Worse, next time I opened the file, the undo history was gone so I had no way to return to my deliberately saved version.

Is this supposed to happen? How do I avoid losing my work next time? Should I be noting the clock time whenever I deliberately save, in case I need to restore from time machine? Or should I be selecting “revert to last saved” before closing a file? Both seem pretty preposterous, so I feel I’m missing something.


This depends on which macOS you are using, and what your Mac system preferences are set to. There hasn’t been a change to OmniGraffle, but your macOS may have changed. OmniGraffle follows your settings from the system if you have these features enabled. It is normal to lose your undo stack if you save or close a document, but by default you should have version history. You don’t have to revert to last saved immediately, you still may be able to recover your data if versions are on. I am assuming you have Sierra, and if so, you can use https://support.apple.com/kb/PH25757 to recover.

Some details from Apple at https://support.apple.com/en-us/HT202255 can explain further. Search for the specific version of macOS you are using for more detailed instructions. If we can help further please choose Contact Omni from the help menu.


Great answer!

After a bit of a journey, I’ve got to the bottom of it. After 25 years of deep, deep familiarity with what a file is and what it means to save, macOS has become more and more bewildering to me. Now, while I’m still yet to see the benefit, at least I can see the logic!

  1. Time Machine is only tangentially related… this threw me initially. On my iMac I have Time Machine running. Closing a file with unsaved changes does as you would expect - prompts you to discard or save. On my MacBook I naturally don’t have Time Machine on. Closing a file with unsaved changes silently “saves” those changes. I say “saves” because saving ain’t saving any more…

  2. Saving ain’t saving any more. I don’t think I can describe any better than done here. The huge take away for me - periodically hitting Command-S is now a bad habit, but only if you’re in an application and on an OS that uses “new save”.

  3. Despite observation #1, there is an option that helps control this behaviour, and it’s no longer associated with Time Machine. In System Preferences->General, there is a checkbox called “Ask to keep changes when closing documents”. Unchecking this restores the expected behaviour. But I expect it’s only there to temporarily placate holdouts like myself.

So, yes Omnigraffle is being a good macOS citizen and following the rules. The rules themselves… are a bit confusing.


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I just lost eight hours of work due to this issue. I can’t believe a large file is overwritten by an empty file without some prompt. The links referenced are 404.


Sorry for the confusion and disruption this caused. As my colleague Lanette mentioned in 2017, this behavior occurs based upon your macOS System Preferences for how unsaved documents are managed, a setting that was introduced in 2011 with Mac OS X Lion 10.7 and impacts a range of applications across your computer.

This forum post is multiple years old, and it appears Apple has moved many of their reference materials around. I’m afraid we’re not able to audit the URLs on our forums on an ongoing basis to maintain their accuracy over time. However, I found the following help article on Apple’s support site with updated information about changing how your computer manages unsaved changes when quitting an app:

Within OmniGraffle, Pages, or any other app that supports macOS auto-save and versioning, you can use File > Revert To to browse prior saved versions of your document.

If you have further questions about how these settings relate to OmniGraffle, or if you would like further assistance in recovering any lost changes—or preventing this from happening again in the future—please email us at omnigraffle@omnigroup.com and we’d be happy to help.