How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Pete Your Own Question
Pete, Computer Engineer
Category: Computer
Satisfied Customers: 18127
Experience:  CISCO certified, Microsoft proficient, computing expert.
Type Your Computer Question Here...
Pete is online now
A new question is answered every 9 seconds

My name is ***** *****, and I want to make a clean El

Customer Question

Customer: Hi. My name is ***** *****, and I want to make a clean El Capitan install. I downloaded the dmg and made a booteable USB drive, but every time I try to boot from the USB I saw a prohibited sign and no errors
JA: Thanks. Can you give me any more details about your issue?
Customer: ask
JA: OK got it. Last thing – JustAnswer charges a fee (generally around $36) to post your type of question to Mac Experts (you only pay if satisfied). There are a couple customers ahead of you. We can help you for less if you're not in a rush. Are you willing to wait a bit?
Customer: ok
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 2 years ago.
Category: Computer
Customer: replied 2 years ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Video Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 2 years ago.
Just a note, it is a Mac related question, not a Microsoft Office...
Expert:  Pete replied 2 years ago.


What method did you use to make the bootable USB drive?

You should try DiskMaker X, and see if that works for you.

If you still get the Prohibited message, then:

  1. Try to boot into single user mode and repair the disk drive.
  2. You could download Recovery Disk Assistant, which you can use to repair your hard drive or reinstall OSX.
  3. You could try mounting the MBPR HD in target disk mode on another Mac, and then repair the HD.