cannot open disk image due to invalid argument

I downloaded a new version of Adobe Flash Player. When I tried to install the new version I got a warning message stating that the disk image could not be opened and the reason was "Invalid argument". I deleted the download and downloaded the version again. Same result. I then tried to install something else that I downloaded and got the same message. Any suggestions? I am using a MacBook Pro with Retina Display (Mid 2015) with El Capitan 10.11.5.

MacBook Pro (Retina, 15-inch, Mid 2015), OS X El Capitan (10.11.5)

Posted on May 31, 2016 12:04 AM

20 replies

WZZZ

Level 6

13,238 points

Jun 1, 2016 9:14 AM in response to Lexiepex

Oops. But why would you be thinking that this could be a User Permissions issue?

Permissions reset can't hurt but, short of a reinstall, and if it is a User issue, perhaps the best course of action for the OP (who seems to be gone) might be to see what happens from a different Account. Create new admin account and test.

Lexiepex

Level 6

14,108 points

Jun 1, 2016 9:12 AM in response to WZZZ

I don't think (now) anymore but that is the third thing promised yesterday...😁

Jun 1, 2016 9:57 AM in response to Lexiepex

Thank you for all the suggestions. Nothing seems to have worked; any dmg that I try to mount gives me the same error and resetting the User Permissions did not help because there was no startup disk to choose when going the route Lexiepex explained (weird!). I have decided to reinstall from a good backup that I have on a time machine. Once again, thanks for all the assistance.

Old Toad

Level 10

215,688 points

Jun 1, 2016 10:55 AM in response to WZZZ

The DiskImageMounter.app can be easily installed without the Terminal by downloading the OS X El Capitan 10.11.5 Combo Update and applying the entire update or use the demo version of Pacifist to install just the DiskImageMounter.app:

WZZZ

Level 6

13,238 points

Jun 2, 2016 8:02 AM in response to Old Toad

The DiskImageMounter.app can be easily installed without the Terminal by downloading the OS X El Capitan 10.11.5 Combo Update and applying the entire update or use the demo version of Pacifist to install just the DiskImageMounter.app:

Yeah, much easier solution than the one I was going to offer. Pacifist with El Cap vaguely crossed my mind, but since I don't run El Cap, it remained vague.

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cannot open disk image due to invalid argument