I was running TTPro in eDrive and I needed more space for a Volume Rebuild. TTPro displayed 151GB free space with 1.07GB contiguous.

So I restarted in Mac HD and trashed 15GB, and my Mac HD finder updated from 151GB to 165GB Available.

So I restarted eDrive and TTPro still displayed only 151GB when I expected to see 165GB, there was no update in free space, it was the same as before I trashed 15GB.

So I restarted Mac HD to see if the restart would update my eDrive TTPro display.

When I restarted eDrive and it updated from 151GB to 155GB, but still not the 165GB I was looking for, it was 10GB short.

So I restarted Mac HD again. Then restarted eDrive again. This time I got the 165GB free space with 3.6GB contiguous that I was looking for.

Why did the update to the new free space size take several restarts? Is this a Mac HD issue or a TTPro issue?

TTPro 8.0.5, Mac OS 10.11.6
MacBook Pro, Model Identifier: MacBookPro8,3
Memory: 8 GB

I do not know how often TechTool Pro updates the free space on a volume. It is possible that closing and then reopening the TechTool Protection system preferences pane would have updated the free space. It takes time to calculate the free space accurately. TechTool Pro is not simply looking at the amount of free space reported by the Finder, which can be inaccurate. The free space reported by the Finder does not take into account any space occupied by files in several invisible directories.

The free space reported by TechTool Pro agrees with the free space reported by the Storage pane of System Information (About This Mac...——>Storage). It just took the Storage pane about 20 seconds to calculate the free space on my Time Machine volume, H_G_Wells: