I can not open my ''dmg'' back-up file format.

I have a back-up file. It is a ''dmg'' file format. The size is 500 GB.
I can not open it in my Mac.

When I click on it I get the error:
''No Mountable File Systems" .

Can someone help me please. I dont wanna losse my backup with all my photos, documents, etc.

Thanks.

It sounds like that DMG didn't actually save properly or is corrupted. I'm afraid there's not a whole lot you can do with it, aside from picking up some recovery software that claims to be able to repair damaged DMG files. Some of that software is rather dubious in quality and it tends to be expensive, so I'd be careful.

The next time you decide to do a backup, I would recommend something that is designed expressly for that purpose like "Carbon Copy Cloner" or "SuperDuper!".

Can you give me the name of one good recovery software please.

Repair dmg files with disk utility.

1. Open Applications, Utilities and open Disk Utility.
2. Drag the DMG file to the left side pane of Disk Utility
3. Select the file and left side, click on 'First Aid' and select 'Repair Disk'.

pjhutch said:

1. Open Applications, Utilities and open Disk Utility.
2. Drag the DMG file to the left side pane of Disk Utility
3. Select the file and left side, click on 'First Aid' and select 'Repair Disk'.

Click to expand...

Hallo,

Thanks a lot for your answer. i did hear this yesterday. but i have not done it allready. I will do it tornight. I need 1 night to do it because it is a big file (500 GB).

Tomorrow if the file is repared. After that? what shaal i do?
Just click on the dmg and it will open?

But if Disk utility can not repared it. Then I can forget it i think. And delete the dmg file?

I will do it. I will come back tomorrow witch the results. Can you please come tomorrow again?

Thanks a lot.