Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Avoid or delete OS X Base System?

B

Bunyak

macrumors member
Original poster
Aug 15, 2011
77
3
I lent my 2011 MBA to a relative for a few years. When I received it back, I erased the SSD and tried to reinstall High Sierra. I was shocked to realize that the OS X Base System was altered to require a username and password from a company unknown to me to finish the installation.

I tried to remove the OS X Base System by erasing the SSD but it won't disappear. I tried the three reinstallation options (Recovery, Internet Recovery, USB installer) but they all bring me to a prompt for a username and password during the installation process. Is it possible to either avoid or delete the OS X Base System?
 
Thanks for the ideas but, for the record, I managed to install the OS normally by not connecting to the Internet until after the OS setup process was complete. I wasn't asked for a username and password. Something is lurking in the MBA, though...
 
OK, then it sounds like this Mac may have been enrolled in DEP. Info here and here. Could be ASM or ABM.

If so, you may have to contact Apple or the original company to remove the machine from the DEP list. Check the discussion here to see if any of this is similar to what you see.

Look in System Preferences for Profiles. Those are one of the primary vectors for MDM management. If you have Profiles, your Mac is talking to an MDM server.
 
Last edited:
  • Like
Reactions: Bunyak
hobowankenobi said:
Generally, yes.

But if the OP got to the point logging in...a Profile could verify the issue, and might help identify the org MDM it is linked to.
Click to expand...
Thanks for the leads. There is no Profiles option in System Preferences so Profiles isn't currently active.

The SSD is the same OWC drive that I installed many years ago. I think that the logic board was replaced when someone spilled liquid on it. I'm guessing that the issue is either the logic board or usage in a corporate network by someone.
 
If the logic board was replaced, it's possible the serial number on the replacement board (assuming it was scavenged from another system) had been set up in DEP and is what is triggering. The serial number is written to the board and special tools are needed in order to change it so it's possible the board was swapped, verified to boot and then the Mac returned to you.

Here's a high level view of how DEP works (possibly covered in links previously posted in the thread):
Corporation registers serial numbers of their computers with Apple and tells Apple how the enrollment is supposed to be handled.
Mac is booted and starts setup.
At some point it wants to connect to the internet. When it does, it "phones home" to Apple to check for an active DEP entry for that serial number. If the serial number is active in Apple's DEP database it then forces enrollment to finish the setup.

Depending on your relationship with the relative, I'd possibly be looking for some kind of compensation if you intended to use that Mac again.

Even though you claim this is YOUR Mac, if we were to get into discussion of bypassing this (I'm not sure how without getting it properly removed from Apple's DEP database) we'd also be giving a roadmap for people that don't have a legitimate need for removing it (stolen Mac).

Bunyak said:
or usage in a corporate network by someone.
Click to expand...
If the system you received back is reporting the same serial number you loaned to your relative and the proper serial number is etched on the bottom cover, it would seem very unusual for a corporation to have set DEP on a device they didn't actually purchase.
 
  • Like
Reactions: Bunyak and hobowankenobi
Hiya friend
the new versions of Macos have recovery volumes
if you reinstall the recovery will do that cheap audit
so either replace the Volume completely or do a low level install
 
@noteuro was that reply intended for this thread? It doesn't make a whole lot of sense when you consider the other replies.
 
Audit13 said:
Check the serial # on the bottom case (assuming the 2011 Air has it printed on the bottom case) to the serial under About This Mac.
Click to expand...

It's almost like someone suggested that already...

hallux said:
If the system you received back is reporting the same serial number you loaned to your relative and the proper serial number is etched on the bottom cover, it would seem very unusual for a corporation to have set DEP on a device they didn't actually purchase.
Click to expand...
 
  • Like
Reactions: hobowankenobi
"OS X Base System" is the Recovery OS (whether booted from Internet Recovery or from the Recovery partition/volume of a HD) - it's RAM-resident and disappears when you're booted normally.
 
  • Like
Reactions: Bunyak
Audit13 said:
Check the serial # on the bottom case (assuming the 2011 Air has it printed on the bottom case) to the serial under About This Mac.
Click to expand...
This thread has been really educational. The serial numbers on the shell and in About This Mac do not match. Therefore, the culprit must be the logic board. Thanks everyone!
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back