The Macintosh HD (in Disk Util, the HD not HD - Data) has been set to the Time Machine disk icon, and the external disk that I use for Time Machine is just the normal icon instead of the Time Machine backup disk icon.
Is there a way to fix this?
iMac Pro
I had this issue too, very strange.
I managed to fix it in the end by copying an image (literally any image), choosing 'File>Get Info' (or Command-I) on Macintosh HD, selecting the icon (so it shows the blue outline) then pasting the image over the Time Machine disk icon, then finally undoing (Command-Z) this action.
This restored the icon it to the correct, familiar grey internal disk, much to my surprise. Hope this works for you.
I had this issue too, very strange.
I managed to fix it in the end by copying an image (literally any image), choosing 'File>Get Info' (or Command-I) on Macintosh HD, selecting the icon (so it shows the blue outline) then pasting the image over the Time Machine disk icon, then finally undoing (Command-Z) this action.
This restored the icon it to the correct, familiar grey internal disk, much to my surprise. Hope this works for you.
Worked great. Thanks.
Macintosh HD has Time Machine disk icon after upgrade to Catalina
