Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Disk Utility: after creating the .DMG (compressed image) When "scan image for restore" finishes it displays "unable to scan (internal error)". Since the process was scanning for about 1 hr is this a fake warning?

External 500GB drive is partitioned with 400GB for Mac OS extended (journalling) and 2nd partition formatted today as "ExFAT".


Yesterday I tried to create a disk image of my HD to no avail - this was compressed on a FAT partition. I got a warning after running the <scan image for restore> saying "unable to scan (internal error)"


I rang Apple support who suggested formatting a partition as MAC OS extended (journalling) and choose to save the image as "read/write'. The image process stopped writing at about 200GB and then the file size jumped to 499GB (ie the size of the HD). But the process did nothing for about an hour so I foce quit disk utility (as suggested by apple support)


My current attempt was to format the external drive again; this time with a 400GB Mac OS extended (journal) format; plus a 100GB ExFAT format partition. The new image was created after about 2.5hrs with a compressed size of 149GB. However, after running the "scan image for restore" facility I got the warning message "unable to scan filename " (internal error). The process was scanning the image file according to the progress bar - this took about hour - thus the warning is a puzzle.


If anyone can say more about this error I would really appreciate knowing tips for using disk utility. The screen grab is below.


"unable to scan filename " (internal error)



User uploaded file


thanks

iMac, Mac OS X (10.6.8), my 1st Apple product - Oct2010

Posted on Apr 9, 2012 12:45 PM

Reply
12 replies

Feb 25, 2017 6:41 AM in response to red4vr

I've just run into this issue after making an image backup of a MacBook Pro runing Lion (10.7.5). I had chosen the option to compress the dmg file. I also was not able to mount the partitions from the backup dmg using Disk Utility - I did get an error message ("no mountable file systems") indicating I should verify the disk with First Aid, even though that check succeeded without errors.


If anyone else runs into this issue, here is a work-around that won't require you to make a new backup in a different way, though you'll need enough extra disk space to create a new copy of your dmg file:


  1. Launch Disk Utility.
  2. From the menu, choose Images, Convert…
  3. You'll be prompted to open a file. Open your dmg file.
  4. Finally, you'll be asked to save the new file. Change the "Image Format:" popup to "read-only" or "read/write" before clicking the Save button.


This should give you a new dmg file that should succeed when using "Scan Image For Restore…".


Good luck.


(And if that still does not work, but you're sure you created the dmg file correctly and didn't damage it afterwards, there's also the possibility to simply open the dmg file and then copy its contents back to your original disk using Terminal commands ("hdiutil attach -nomount ..." and "dd") or my tool iBored. However, that requires some more care and deeper technical understanding of disks and partitions in particular. I may, if there's enough interest, write a blog article on blog.tempel.org on it.)

Apr 10, 2012 2:39 AM in response to baltwo

Thanks for a quick reply <baltwo>. You’ve answered that it is not a fake message!


fyi: I thought that I would use my external Buffalo for two purposes; namely the smaller ExFAT partition for copying stuff to my win7 netbook. The larger partition was to be used as my imac image of SL. So this was my first attempt at using disk utility - the idea being to hold an image backup at another location. Plus I now have the Lion thumbdrive ready to upgrade from SL and so being cautious wanted to have a SL image backup


Anyway I followed the apple instructions using my mac 10.6.3 install DVD but it would appear from other discussions that <unable to scan (internal error)> is not unique to me.


I’ll get back to apple telephone support for further advice.


I would though be grateful for an “idiots’ guide to making an image backup of my internal HD that runs SL 10.6.8


eg should I have just one partition on the external USB drive? format it as Mac OS extended? create the image as compressed or read/write? Basically I’ll do whatever will work!!


thanks again

Apr 10, 2012 12:25 PM in response to red4vr

I never recommend making images, since they're not bootable; whereas bootable ones (I prefer using Carbon Copy Cloner) on a separate HFS+ formatted FWHD, using the GUID partition map, works a treat. IMO, I'd dispense with attempting to do windoze and Mac stuff on the same HD. Details on making the bootable backup/clone are in


http://www.macmaps.com/upgradefaq.html

http://www.macmaps.com/backup.html

http://www.thexlab.com/faqs/installswupdates.html

http://www.thexlab.com/faqs/backuprecovery.html

Apr 11, 2012 10:26 AM in response to baltwo

ok fine. I'll switch my focus to making a clone as the apple software seems too troublesome (like someone else said somewhere "why get to the end of a process before putting up an error message" - seems disk utility is not user friendly) & I'll read your links.

thanks

ps nice climate you have on the west coast - lucky for some!

Aug 2, 2012 1:19 AM in response to red4vr

I have exactly the same problem on my Mac Pro using Mountain Lion. I create a dmg file with Disk Utility of my boot parition and save to my data hard drive. When I try a restore to a spare boot partition I always get an internal error on the dmg file. I have verified the boot partition and thats good. I have disabled the verify checksums in Disk Utility. The restore used to work fine under Leopard using Disk Utility and now no longer works under later versions of the OS. This only leaves SuperDuper or Carbon to create a clone which is not what I want. Please Apple sort this out some time soon.

Nov 20, 2013 8:40 AM in response to red4vr

The Disk Utility works to create successful imaging files. However, the Disk Utility tool will not work to image/restore the OS partition/drive while the OS is running. You must boot into the recovery tools...i.e. shut down and then when you power on hold down {Command}{r} or {option}...you can also use the Mac startup disk if that's an option for you. This will ~boot you into recovery tools. Choose Disk Utility, click on your bootable partition you want to image (normally 'Macintosh HD') and select new image. Test it out when complete by choosing restore and runnng scan. You must use the same boot process to recover your OS partition if needed in the future.


Here's a link to the various steps...it's ok but needs to be updated. http://support.apple.com/kb/ht1553


Hope this is helpful,

Mike

Disk Utility: after creating the .DMG (compressed image) When "scan image for restore" finishes it displays "unable to scan (internal error)". Since the process was scanning for about 1 hr is this a fake warning?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.