removing jamf from iMac - reality check

[Jason Davies]

Hi gang,

We have an iMac that was set up as dual-boot. I never used the 'UCL version' of the boot. Somehow the version of iMovie has got out of sync with the OS (too old or new, not sure).

I tried updating the system to 14.6 from 14.3 (those numbers from memory) so we could use iMovie again but it stalled halfway through (three times, via different methods). I decided this was probably the management software (jamf).

Conversation with ISD has ended up with them deregistering it with jamf and advice: 'The device will need to be wiped and reset in order to remove managed config.'

They then sent me the link to Erase Apple devices – Apple Support (UK)Opens a new window

I have done this kind of thing too many times to expect it to be simple so would appreciate any reality checks. I'm getting quite laconic replies so hope some of you are more 'hands-on' with this, and know the twists and turns of doing this in practice.

• the machine no longer has an ethernet connection (moved from original room) so has to be logged into a (weak) wifi signal by each user. The room does not apparently have any ethernet cabling in it.

• that document talks about 'Erase all content and settings' which is not the same as 'wiped and reset'. It will be much easier to do the former as it retains the OS. Otherwise I assume I'm looking at a remote (very slow) reinstall of the OS. I think my question is 'at what depth does jamf function?' It intercepts the machine for you to agree to UCL policies before you can login. Will Erase all content and settings get jamf out of the machine?

• does jamf know it's disabled on the machine if a different user than the UCL admin logs in? We do have an admin user account on it.

Because it takes so long (hours) to download even a moderate size OS update and I'm generally only in one day a week, I can't just leave it running/updating.

Basically, this is a fishing trip in the lake of your collective experience: what kind of hitches should I expect? I can't leave the machine disabled for a week if it fails after I've gone home that day;)

Cheers,

Jason

[Sam - MacAmbulance]

If you have a Mac on a faster internet connection and a spare external usb drive, I’d make a usb installer of whichever version of macOS you’re going to install.

https://support.apple.com/en-us/102662 has links to the macOS installers, then use terminal and (for example) :

sudo /Applications/Install macOS Sequoia/Contents/Resources/createinstallmedia --volume /Volumes/ExternalVolume

(ExternalVolume being the name of the external drive which you want to use, it’ll be erased)

Then you can boot up the other Mac holding alt/opt and select the installer drive. You can then use disk utility to repartition the internal drive and install macOS afresh

_

Regards Sam Mullen +44 (0)7747778022 in...@macambulance.com www.macambulance.com MacAmbulance Ltd. Providing Affordable Mac/PC Support and Web Development

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On 17 Jul 2025, at 13:56, 'Jason Davies' via Sussex Mac User Group <sm...@googlegroups.com> wrote:



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[Jason Davies]

Thanks Sam, and apologies, I meant to send that to the UCL Macuser group (thus the way it's written).

I did try that with the minor update but it stalled, like everything else. It might allow it if jamf is disabled now. It's definitely on my list. If I'm honest, I don't trust the advice I was given because they support PCs 99% of the time and don't know about the security measures on Macs. I'm hoping not to end up in a cycle of 'ok, Plan C didn't work, let's try Plan D'. If I try to install a whole new OS, it might mean sitting there until the early hours while it runs;)

On 17 Jul 2025, at 15:35, Sam - MacAmbulance wrote:

> If you have a Mac on a faster internet connection and a spare external usb drive, I’d make a usb installer of whichever version of macOS you’re going to install.

Cheers,

Jason