Upgrading to Monterey - Storage system verify or repair failed : (-69716)

How much free storage space do you not have? You need 26GB.

Do you still have the Monterey installer? It is located in the Applications folder. You can move that to Trash and empty the trash.

If you go to Disk Utility and make sure each entry is fully expanded (⌵ symbol points down ⌵ and not >. Also that in View (top center) is checked to show all devices. Take a screenshot of Disk Utility and post it here:\.

To take screenshot

Take a screenshot on your Mac - Apple Support

To add it to a reply

Click on the add image icon right below the test entry box

After clicking on the icon you are present with a Finder like windows. maneuver to find the image file you want to post and click on it and select Open in bottom right or double click on the image file to add the image in the text reply box.

What @coxorange posted in the screen shot is normal. Nothing needs to be deleted.

I believe that snapshot com.apple.os.upd... on the Macintosh HD volume to be the Sealed System Volume snapshot, and must not be deleted. Even if you did delete it, in all likelihood no space would be reclaimed. The SSV snapshot is a read-only version of the of Macintosh HD volume, and is what macOS boots from. The underlying Macintosh HD volume does not get mounted to the operating system, and nothing gets written to it during normal operation. Since Macintosh HD does not change, no extra blocks are used to maintain the snapshot.

Macintosh HD will only be changed during OS maintenance (update/upgrade/security patches), and the installation process deletes and re-creates the SSV snapshot after the system update completes.

You should be able to delete the Snapshot com.apple.os.up... to free up space.

However, the Fusion drive may be failing/have problems if you get the "Storage system verify or repair failed : (-69716)"

error when install Monterey.

This error message " (-69716) " appears to be a Split Fusion Drive that needs to repaired

When a Contributor of such long standing mentioned possible Fusion Drive acting up / failure - I tend to heed the advice