Unable to eject Time machine back up, anyone have other suggestions what I can try?

My Time machine backup has been working well but recently been unable to I checked the time machine back up. The only solution I find online is to restart the computer which I'd rather not do

I've looked on a number of forums nothing suggested seems to be working. All my software is up-to-date and I wonder if there's a setting that has changed but I'm not aware of. Any thoughts or suggestions from the community welcome