Disk utility asks for password for authopen when creating images

I've run into the same issue, running 10.8.1. I have narrowed down the problem a little - it appears to be the new version of Disk Utility that is causing issues. I don't know how to fix the 'authopen' part of the problem, but as a workaround for the 'no eject' part, just quit Disk Utility and relaunch it. It will then mount the CD and the partitions on it, and allow you to eject them properly.

For what it's worth, if you do (in a Terminal window) a 'ls -la /dev/disk*', you will note that while the overall disk is owned by you, any partitions on it after you let Disk Utility have its way will be owned by root, which doesn't seem correct. The user in the current GUI session should own any disks mounted, as well as their partitions. In Lion, even after Disk Utility has unmounted a disk so it has exclusive access to it, after it was done the disk and its partitions were owned by the GUI user, not root.

Good luck figuring out a solution - I'll have to test another 10.8 install to see if the problem is machine specific or general to 10.8.

I did not see this posting and have posted exactly the same question as I too am having this problem.

I'm seeing the exact same issue w/ a brand new Retina MBP running 10.8.3.

Thanks, Apple, for requiring a "root" or Admin password for simply cloning a flash drive, disk, or folder for transfer to another system.

I confirmed with a call to AppleCare yesterday: this is a 'security feature' introduced in 10.7 Lion & 10.8 Mountain Lion; so that any standard (non-administrator accounts) require permission from an admin to create any disk image via Disk Utility.

Having tested last night with an old 10.6 Snow Leopard install, I can confirm this version is the last Apple operating system that will not demand admin credentials to create a disk image (although haven't tested 10.7 Lion yet, but the AppleCare rep stated both 10.7 & 10.8 were changed in this way).

As it's a basic necessity to backup SD Card media etc while logged in as a standard account (especially for students studying new media via Apple Mac's in education); I find this a very frustrating artificial limitation, with no official work around (or notice of this change anywhere). I assume any standard users without an admin username & password, simply cannot create a DMG via any built in software; requiring System Administrator permission each time; or the install of a third party App without this 'security feature' to complete a basic backup.

To get around this issue, the group name needs to be changed to 'everyone' in the sys.openfile section of /etc/authorization. You will still need to authenticate, but you do not need to have admin credentials:

<key>sys.openfile.</key>
        <dict>
            <key>class</key>
            <string>user</string>
            <key>comment</key>
            <string>See authopen(1) for information on the use of this right.</string>
            <key>default-button</key>
            <dict>
                <key>ar</key>
                <string>فتح</string>
                <key>ca</key>
                <string>Obrir</string>
                <key>cs</key>
                <string>Otevřít</string>
                <key>da</key>
                <string>Åben</string>
                <key>de</key>
                <string>Öffnen</string>
                <key>el</key>
                <string>Άνοιγμα</string>
                <key>en</key>
                <string>Open</string>
                <key>es</key>
                <string>Abrir</string>
                <key>fi</key>
                <string>Avaa</string>
                <key>fr</key>
                <string>Ouvrir</string>
                <key>he</key>
                <string>פתח</string>
                <key>hr</key>
                <string>Otvori</string>
                <key>hu</key>
                <string>Megnyitás</string>
                <key>it</key>
                <string>Apri</string>
                <key>ja</key>
                <string>開く</string>
                <key>ko</key>
                <string>열기</string>
                <key>nb</key>
                <string>Åpne</string>
                <key>nl</key>
                <string>Open</string>
                <key>pl</key>
                <string>Otwórz</string>
                <key>pt</key>
                <string>Abrir</string>
                <key>pt-PT</key>
                <string>Abrir</string>
                <key>ro</key>
                <string>Deschide</string>
                <key>ru</key>
                <string>Открыть</string>
                <key>sk</key>
                <string>Otvoriť</string>
                <key>sv</key>
                <string>Öppna</string>
                <key>th</key>
                <string>เปิด</string>
                <key>tr</key>
                <string>Aç</string>
                <key>uk</key>
                <string>Відкрити</string>
                <key>zh-Hans</key>
                <string>打开</string>
                <key>zh-Hant</key>
                <string>打開</string>
            </dict>
            <key>default-prompt</key>
            <dict>
                <key>ar</key>
                <string>يحاول __APPNAME__ فتح الملف الذي تم اختياره.</string>
                <key>ca</key>
                <string>__APPNAME__ està intentant obrir l’arxiu seleccionat.</string>
                <key>cs</key>
                <string>__APPNAME__ se pokouší otevřít vybraný soubor.</string>
                <key>da</key>
                <string>__APPNAME__ forsøger at åbne det valgte arkiv.</string>
                <key>de</key>
                <string>__APPNAME__ versucht, die gewählte Datei zu öffnen.</string>
                <key>el</key>
                <string>Η εφαρμογή __APPNAME__ προσπαθεί να ανοίξει το επιλεγμένο αρχείο.</string>
                <key>en</key>
                <string>__APPNAME__ is trying to open the chosen file.</string>
                <key>es</key>
                <string>__APPNAME__ está intentando abrir el archivo seleccionado.</string>
                <key>fi</key>
                <string>__APPNAME__ yrittää avata valittua tiedostoa.</string>
                <key>fr</key>
                <string>__APPNAME__ essaye d'ouvrir le fichier sélectionné.</string>
                <key>he</key>
                <string>״ __APPNAME__״ מבקש לפתוח את הקובץ הנבחר.</string>
                <key>hr</key>
                <string>__APPNAME__ pokušava otvoriti odabranu datoteku.</string>
                <key>hu</key>
                <string>A(z) __APPNAME__ megpróbálja megnyitni a kiválasztott fájlt.</string>
                <key>it</key>
                <string>__APPNAME__ sta cercando di aprire il documento prescelto.</string>
                <key>ja</key>
                <string>__APPNAME__ は、選択中のファイルを開こうとしています。</string>
                <key>ko</key>
                <string>__APPNAME__이(가) 선택된 파일을 열려고 합니다.</string>
                <key>nb</key>
                <string>__APPNAME__ prøver å åpne den valgte filen.</string>
                <key>nl</key>
                <string>__APPNAME__ probeert het gekozen bestand te openen.</string>
                <key>pl</key>
                <string>__APPNAME__ próbuje otworzyć wybrany plik.</string>
                <key>pt</key>
                <string>__APPNAME__ está tentando abrir o arquivo escolhido.</string>
                <key>pt-PT</key>
                <string>O __APPNAME__ está a tentar abrir o ficheiro escolhido.</string>
                <key>ro</key>
                <string>__APPNAME__ încearcă să deschidă fișierul ales.</string>
                <key>ru</key>
                <string>Программа «__APPNAME__» пытается открыть новый файл.</string>
                <key>sk</key>
                <string>__APPNAME__ sa pokúša otvoriť vybraný súbor.</string>
                <key>sv</key>
                <string>__APPNAME__ försöker öppna den valda filen.</string>
                <key>th</key>
                <string>__APPNAME__ กำลังพยายามเปิดไฟล์ที่เลือก</string>
                <key>tr</key>
                <string>__APPNAME__, seçilen dosyayı açmaya çalışıyor.</string>
                <key>uk</key>
                <string>Програма «__APPNAME__» намагається відкрити вибраний файл.</string>
                <key>zh-Hans</key>
                <string>“__APPNAME__”正试图打开所选文件。</string>
                <key>zh-Hant</key>
                <string>“__APPNAME__”正在嘗試打開所選檔案。</string>
            </dict>
            <key>group</key>
            <string>everyone</string>
            <key>shared</key>
            <false/>
            <key>timeout</key>
            <integer>300</integer>

amferell is correct; this was impacting our educational environment (similar to BenHudson's workflow) and this worked in my tests...haven't tested with an AD account but should work as the standard account I tested with worked. be sure to login as root when editing the file.

thank you amferell! saved me some time this morning and i appreciate it!