Why is "Verify Backups" in the Time Machine icon menu disabled?
&quot;Verify Backups&quot; is applicable only to backups on network drives.  It will be greyed out if you are backing up to a local drive.
Apple should have been clearer in indicating this.
From Finder &gt; Help &gt; Verify your backup disk

Verify your backup disk
If you back up to a network disk, Time Machine periodically verifies that your backups are in good condition. If you like, you can perform a verification at any time.

Open the Time Machine menu in the menu bar, press the Option key on your keyboard, and then choose Verify Backups.