how to get one number missing on serial number

I think the first character may be the letter "Q".

See if you can scan the bar code with your phone. You may need to get an app that can read bar codes.

The third character indicates the year of manufacture which in this case is an "8" for 2008. The fourth & fifth characters indicate the week of manufacture so this was manufactured in the second week of Jan. 2008 so this could be a mid-2007 or early 2008 model. I believe both models can have macOS 10.11 El Capitan installed.

In order to create a macOS 10.11 USB installer you will need access to another Mac capable of running macOS 10.11. Here is the Apple article on how to create a bootable macOS USB installer including links to download various versions of macOS.

While macOS 10.11 can still be useful and can run current versions of third party browsers such as Firefox, Chrome, and Vivaldi I don't expect these browsers to support such an old OS for much longer.

While you are unfamiliar with Ubuntu it is a good choice for older Macs especially if the Mac has 4GB of RAM installed. You should definitely consider it at some point when macOS 10.11 becomes to old to support current third party web browsers. Kubuntu, Ubuntu-Mate, and Linux Mint would be good choices as these versions look nice and can run with as little as 4GB of RAM and they are all easy to install on a Mac. They are all also good choices when learning and getting familiar with Linux. The default Ubuntu with Gnome is not a good choice for older systems.

You definitely want to erase the drive and start over no matter what as you want to start with a clean install of an OS whether it is macOS or Linux.

• The first three digits represent the manufacturing Location.
• The next two indicate the year and week of manufacture.
• The next three digits stand for a unique identifier.
• The last four digits represent the model number.

https://igotoffer.com/apple/apple-serial-number-why-is-it-important

If the serial number is 12 characters long, the iMac was manufacturered after 2010, and if true, then you only need the last four characters to determine the market introduction year of the iMac. I do not believe this will work for 11 character S/N prior to 2010.

In a browser, enter the following, where the XXXX is the last four characters of your 12 character serial number:

https://support-sp.apple.com/sp/product?cc=XXXX

In Firefox 75, this should return a string like the following which was returned for my Late 2013 iMac. Safari 13.1 will download a text file [product] that you can click, and use the spacebar to Quick Look the following string format for your iMac:

<?xml version="1.0" encoding="utf-8" ?><root><name>CPU Name</name><configCode>iMac (27-inch, Late 2013)</configCode><locale>en_US</locale></root>



where the information of interest to you will be in parenthesis. Once you have the Early, Mid, or Late prefix and year, you can get more detailed information on your iMac from Everymac.

Plan B. If the serial number is less than 12 characters, or the preceding did not work for you, then get the EMC number from the bottom of the iMac stand and enter that number in the following location:

on this everymac site. It will return information on the iMac models covered by that EMC number.

Based on the information you derive from the preceding, let us know what the parenthetical market introduction string is, or the EMC number so we can look it up on the everymac site and skip your screen capture of that information.

...older imac...

Please help us help you Can you give us more? iMacs have been in continuous production for 22 years and in thousands of variants making is nearly impossible to help with so little information. Serial number styles and locations are not consistent. We need you to narrow down the sub-model. Post a picture of the computer is you have to, but don't post the partial serial number; the Hosts will remove it.

BDAqua wrote:

• The first three digits represent the manufacturing Location.

Hey BD, remember the video display fiasco that affected so many G5 iMacs and early Intel iMacs? That factory code was W8--two characters. I think we're stuck until OP gives us a better idea of when this was made.

It would be a lot easier if the iMac were running macOS even in a small partition. I don't know Ubuntu so can't offer a utility that can return the and serial number like we can in Terminal.

Guys,

I read OP's post as that he needs the serial number to have Apple check to see if they still can furnish system software. All he is missing is the first character which is obliterated on his computer.

Even with a full model description, Apple Support asks for a full serial number to check if OS software is available to order. Been there, done that. Apparently Apple cannot search from a partial serial number.

Agreed. No means to get that missing first character of the S/N, or Apple lookup with it missing.

However, if we know the Mac market introduction date, and supported software is still available from eBay (e.g. Snow Leopard), or downloadable from Apple sources on another Mac to build an install media, then it might be a step in the direction of replacing Ubuntu on that iMac.

Were you given the password for Ubuntu and Are you able to access the Ubuntu desktop? Maybe the password was set to blank if you weren't given one. If so, then I can provide you with a command which can retrieve the system serial number.

Take a picture of the first couple characters of the serial number and maybe we will be able to tell what the damaged character is supposed to be. Please do not post the whole serial number here. We only need the first couple characters.

Is this a white plastic iMac or an Aluminum iMac?

Excellent answer @HWTech !

either mid-2007 or early-2008 iMac runs fine nowadays El Capitan with better usage than Ubuntu.

The OP can {considering just to be sure about the serial] install ElCapitan on it using any external USB portable HD, without erasing the internally installed Ubuntu.. than just remove the USB HD after getting the Serial Number

Or go further and enjoy a good experience using El Capitan on that iMac

I have one iMac early 2008 here by my side which is perfect for Internet, Microsoft Excel, e-mails, having iTunes synced with my Apple Music account, and plays perfectly youtube videos at 1080p... with 4GB RAM

There was still a recent security update for it from Apple recently (on Jan/2020) and Apple keeps updating El Capitan with the latest MRT (Malware Removal Tool) version and Sys Policies synced/aligned exactly at the same Mojave and Catalina security packages.

You don't have Music App, nor any modern app. But it has a secure updated system, has an updated Safari, and everything else for daily usage. It does not have: Siri, Dark Interface and Airdrop.. but full iCloud sync and everything else is being updated. On El Capitan, with 4GB RAM, it runs fine Parallels 13 with Windows7 VM, really fine.

I lost the focus of the question... Sorry... Lol

I agree with you:

install El Capitan on any external USB HardDisk, get the Serial on "About this Mac".. takes 40min of your life, and problem solved.

:)

I don't remember that & now I'm doubting my link,Country is D25??? & my Mid 2011 iMac was made in last half of 2012???

Hey, let's try this: please tell us the second and third characters--no more-- of your serial number and perhaps we can figure out by process of elimination what factory code yours has.