Glad to solve your problems, this case may contribute to the local snapshots of Time Machine, the purgeable space on Mac, System glitches, disk errors, etc.
(1)Restart your Mac.
(2)Try to enter Mac Safe Mode.
(3)Delete purgeable space with effective software. iBoysoft DiskGeeker can do this perfectly.
- Free download, install, and open it.
- Select the target drive from the startup disk and click Clean Junk from the right toolbar.
- Select a folder from the left to view the contents.
- Select unwanted ones and click Clean > OK.
(4)Erase local snapshots with Terminal.
(5)Reindex Spotlight.
(6)Repair the drive with Disk Utility.
Also read: macOS Shows Wrong Free Space in Disk Utility/Finder.
