iMac stuck installing El Capitan, please help!

[Geronimo]

Last night I tried to download an update to El Capitan for my early 2008 iMac version 8.1.
(I was previously running OS X Lion 10.7.5), however it is now stuck on the installation screen with just a small amount of the progress bar filled. I have tried powering it off and restarting several times but it comes back to the same screen. I have also left it for several hours but it doesn’t progress.
How can I return it to the original system?

 

[honestone]

Need some more information:

1. This is critical: have you been making backups to an external device? If you have, what software have you been using for that task?

2. Have you ever done any disk cleanup/maintenance/repairs, from a software perspective? You actually can do quite a lot ot disk cleanup on your own, and there are some excellent programs available (both free and commercial) to help with those tasks.

3. How are you making posts here? If it's with another Mac, what exact model is it?

4. Did you just try to upgrade "in place", ie, let El Capitan basically overwrite what was on your machine already?

 

[Geronimo]

Need some more information:

1. This is critical: have you been making backups to an external device? If you have, what software have you been using for that task?

2. Have you ever done any disk cleanup/maintenance/repairs, from a software perspective? You actually can do quite a lot ot disk cleanup on your own, and there are some excellent programs available (both free and commercial) to help with those tasks.

3. How are you making posts here? If it's with another Mac, what exact model is it?

4. Did you just try to upgrade "in place", ie, let El Capitan basically overwrite what was on your machine already?

Hello and thanks for your reply. In response to your questions,

1. It is my sister’s old machine and when used previously it was backed up using Time Machine but before giving it to me she wiped it and did a new system install from USB.
It has not been backed up since but didn’t have anything important on anyway.

2. Since receiving the newly wiped machine I have not done any disc cleanup, etc.

3. I am posting here from my iPad Pro 9.7”, don’t know the exact model but can get the cover off and check the serial number online if necessary.

4. I did try to upgrade ‘in place’ as wasn’t bothered about contents of machine.

Many thanks for your help.

 

[honestone]

Given that you do not need anything on the machine, it might be best to try a clean, fresh, "virgin" installation of El Capitan. To do that, assuming it can still be done, boot you iMac via the (hidden) Recovery HD partition, described here:

https://support.apple.com/en-us/HT201314

However, note the following:

https://support.apple.com/en-us/HT204904

So, I am not sure which of those keyboard combinations will get you El Capitan, OS 10.11.6. Yet, according to this:

https://everymac.com/systems/apple/...20-inch-aluminum-early-2008-penryn-specs.html

the maximum OS your machine can support is El Capitan. So, the keyboard combination you want to use to boot from the Recovery HD partition is Option-Command-R.

Once you do that, first select the "Disk Utility" option from the screen that appears. Have it first Verify and Repair the internal drive. If everything is OK, then let it Erase and Format the drive.

After that is done, select the choice "Reinstall macOS". That should get you V10..11.6 of El Capitan, from the App Store. Be aware that process will take some time. After it completes (hopefully successfully), when you restart your iMac, you will need to go through an entire setup, just like getting a new Mac.

One caveat: if Disk Utility reports an issue with trying to repair your internal drive, then you cannot proceed any further without further analysis. If that is the case, most likely the internal drive would need to be replaced.

 

[Geronimo]

Given that you do not need anything on the machine, it might be best to try a clean, fresh, "virgin" installation of El Capitan. To do that, assuming it can still be done, boot you iMac via the (hidden) Recovery HD partition, described here:

https://support.apple.com/en-us/HT201314

However, note the following:

https://support.apple.com/en-us/HT204904

So, I am not sure which of those keyboard combinations will get you El Capitan, OS 10.11.6. Yet, according to this:

https://everymac.com/systems/apple/...20-inch-aluminum-early-2008-penryn-specs.html

the maximum OS your machine can support is El Capitan. So, the keyboard combination you want to use to boot from the Recovery HD partition is Option-Command-R.

Once you do that, first select the "Disk Utility" option from the screen that appears. Have it first Verify and Repair the internal drive. If everything is OK, then let it Erase and Format the drive.

After that is done, select the choice "Reinstall macOS". That should get you V10..11.6 of El Capitan, from the App Store. Be aware that process will take some time. After it completes (hopefully successfully), when you restart your iMac, you will need to go through an entire setup, just like getting a new Mac.

One caveat: if Disk Utility reports an issue with trying to repair your internal drive, then you cannot proceed any further without further analysis. If that is the case, most likely the internal drive would need to be replaced.

Thanks again for your advice.

I will need to get a usb keyboard as presently using a wireless and obviously can’t connect until machine is running so it’s useless for this task. Shouldn’t be a problem borrowing one though. Once I have another keyboard I will follow your directions.

Many thanks

 

[honestone]

Not sure why a wireless keyboard will not work, but that's OK. Let is know how it goes, and good luck!