While adding some annotations to a PNG image, using the Preview App, I added a mask to highlight part of the image -- Shapes » Highlight. After doing that I couldn't save the image anymore. I got the following error message:

The document "[FILE_NAME]" could not be saved.

Error message: The document could not be saved

No detail about what is wrong was given. I tried different file names and directories. Also tried to use "Export" instead of "Save". Nothing worked.

Looking at Apple's support page I couldn't find anything about a specific format or something special about that tool.

I'm wondering what I'm doing wrong.

  • 1
    png doesn't support layers, though idk why you couldn't export as something that does, pdf, tga etc – Tetsujin Jan 19 '18 at 13:30
  • Maybe it's a just a missing feature but I expected for Preview to merge the layers when saving a PNG as other image editors do. At least when using the Export action. Or display a clearer error message. – Gustavo Straube Jan 19 '18 at 13:36
  • I had no problem saving a PNG file with applied Mask in Preview under macOS 10.12.6. I saved it, closed it and opened it and it was as should be, with the mask. What version of macOS and where is the original file stored? Also have you tried rebooting and get the same results? – user3439894 Jan 19 '18 at 13:49
  • 4
    This looks to be an issue with macOS 10.13 because it works as expended in previous version macOS 10.12. Anyway, under macOS 10.13.1 I got the same error as you when trying to just save it but could export as PDF. – user3439894 Jan 19 '18 at 14:48
  • 1
    @Marklar Unfortunately, I didn't. I'm simply not using that feature. – Gustavo Straube Feb 27 '18 at 18:55

This is a bug with Preview.

Preview -[CIImage initWithCGImage:options:] failed because the CGImage is nil.
Preview Error: CGImageForSavingWithFlattenedEXIF:depth: failed
Preview finalize:2403: image destination must have at least one image

You can report bugs to Apple at https://bugreport.apple.com.

  • Bug submission is no longer supported there. ... and this feature is still broken. – musicin3d Sep 4 at 19:04

I am having exactly same issue on my end. not able to save highlighted picture in preview app

Highlight is a function I need to use everyday. Hope Apple fix this as soon as possible.

Current stupid workaround is

  1. Use preview to set highlight area.
  2. Use command+shift+4 to take screenshot on preview.


  • I didn't think of taking a new screenshot. It's more work but it works. Haha! – Gustavo Straube Jun 12 '18 at 15:13
  • does someone have time to tell me how to highlight a paragraph? I'm not even sure what highlight does. – jmh Jun 12 '18 at 18:10

Export to PNG before making changes. Open the PNG file and edit it. Use Instant Alpha to delete background. Finalize and save. For other changes I suggest exporting it to JPEG or other


Alternative solution to screenshot...

  1. Cmd + Shift + S to duplicate
  2. Cmd + S to save
  3. Save as PDF
  4. facepalm for just a moment
  5. edit
  6. Export as PNG

Not really sure it's a better solution, just another workaround.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .