IMac won’t boot more than half way, the bar just stops. Have tried booting in to safe modes Nf resetting the PRAM but it doesn’t recognise any keyboard input

I will add this. (1) My Mac was performing at its finest with no issues or problems. (2) I installed a commonly used app which also needed their additional app to function on Mac external drives. Something unforeseen occurred. Sometimes it just happens. A bit of data somewhere conflicts with another bit of data somewhere else and a problem occurs. Pre-release testing of an app can never find or address every potential issue that might pop up. Then it's reformat time!

Your Mac is apparently not recognizing a wireless keyboard. I suggest connecting a wired keyboard so you can do needed entries. (That is why I don't like wireless keyboards and Mice.) Also, it sounds like you may have updated or upgraded your operating system and it can't properly open because it's corrupted. I suggest that you reinstall the OS using a wired Ethernet connection and not Wi-Fi as it often fails.

I recently had a similar experience. It was caused by an app I installed. It corrupted my OS so it would not complete the startup process. I too reloaded the OS and tried Disk Utility to repair it. Nothing worked, so I had to reformat the drive and then go through the process of installing a clean new OS and then transfer all my backup files. Thank you for backups! That may be your resolution.

Follow each steps at > If your Mac starts up to an Apple logo or progress bar - Apple Support

Then if you still need help > contact Apple Support.

Hi there!

When you reinstalled macOS, do you recall what version it installed? Do you know what year your Mac is? Also, do you have a backup of your Mac?

Jack

Thanks for the info! Do you know if you have a backup of your Mac?

Jack