Time Machine Icon on Desktop showing the yellow icon
To fix this I went into Get Info for the external drive and under the "Preview:" section it showed the TM icon, which I clicked and dragged to the top of Get Info and it overlayed the yellow icon.
For me it fixed by following these steps:
- Go to
System preferences > Time Machine - Go to
Select Disk... - Select the disk which is showing yellow icon
- Start the backup
This will remark the disk as Time Machine Backup and macOS will change the icon to the Time Machine green icon.