Can I reinstall Monterey on my iMac without having to do a full restore of data?

Does one mean via this method >>

Use Disk Utility to erase an Intel-based Mac and then How to reinstall macOS

Or

Reinstall macOS over itself to put back corrupted or missing elements of the OS. This is done via Recovery Mode and choose Reinstall macOS.

Very likely yes.

You need iMac introduced in late 2015 or later

Do you have enough free disk space?

If upgrading from macOS Sierra or later, your Mac needs 26GB of available storage to upgrade. If upgrading from an earlier release, your Mac needs up to 44GB of available storage.

Also uninstall any antivirus and "cleaning" apps before trying installing again.

Further, you need an Apple disk installed to upgrade to Monterey since the upgrade includes an update to the Mac's firmware. That update looks for an Apple disk and write to the dick to do the firmware update. The install will terminate or freeze if no Apple disk.

Some users have problem with skipping upgrade versions and even not updating to the latest version of Big Sur.

Make sure you have a good backup in case something goes wrong

An Apple disk is a disk internal to the Mac that is supplied by Apple. In some Macs the disk can be replaced with a commercial/non-Apple disk. you need an Apple disk installed to upgrade to Monterey since the upgrade includes an update to the Mac's firmware. That update looks for an Apple disk and write to the dick to do the firmware update. The install will terminate or freeze if no Apple disk is installed.

akfromnyc wrote:

Thanks. What is an Apple disk - never heard of such a thing!

If you boot into recovery you can reinstall Monterey without it erasing your data. But always have a backup just in case.