How Do I Get Disk Utility To Display the Correct Values?

I have only 32 GB free on Macintosh HD and want to make more space by deleting some files.
Many, many files have been copied to an external drive and deleted from Macintosh HD and
the trash has been emptied. I can verify this with the Finder. However Disk Utility still
shows only 32GB free on Macintosh HD. Quitting Disk Utility and restarting doesn’t help
nor does restarting the computer.
Disk Utility needs to display the correct value.
This is important since I have an App that will not
run unless there is more free space on Macintosh HD.
—–
Paul