Prevent scheduled defrag from consolidating free space?

It seems that Windows 8.1 Pro's scheduled defrag is consolidating free space, which is taking forever on one of my 2 TB data drives, which has about 300 GB free space. I stopped it at about 9%, and dfrgui immediately showed it as "OK (0% fragmented)". Clicking its Optimize button resulted in the defrag phase completing almost immediately, but then it was back to consolidating free space, starting at 5% this time. According to Task Manager, it's read/writing about 40 MB/sec, and the Active Time is over 90%. I really don't want this to go on for hours and hours and potentially repeat itself during future scheduled scans. Is it possible to alter this behavior, or should I just disable the weekly defrag task?

Everyone has their own defrag methodology. I like frequent "light" defrags. An example is Auslogics Defrag with no optimizations. I run it manually 4 or 5 times a week. Unless I have been doing a lot of downloads and installs, it usually defrags my C: partition in less than 5 minutes. Granted C: has about 80% capacity free. Much faster with lots of room to work.

Right, but that disables defrag on a drive, and I'd have to monitor what it's doing on the drives for which I leave it enabled to see if it's entering the endless thrashing consolidation phase. If I am to leave scheduled defrag enabled, I need to eliminate the free space consolidation phase. Does anyone know if this is possible?

You don't have to use the MS defrag Many free defraggers have scheduling. I've used 3rd party defraggers on Windows almost exclusively. So I can't give a confident answer.

The trouble with using MS defrag in task scheduler is it doesn't detect a busy disk unless they changed it since Vista. You can be running a 3rd party defrag and have MS defrag start right in the middle of it. Not wise.

I know about 3rd party defraggers. My question is about the one provided by Microsoft in Windows 8.1 Pro.

crawfish said:

...I need to eliminate the free space consolidation phase. Does anyone know if this is possible?

Click to expand...

Not possible, eliminating the consolidation process would defeat the whole purpose of running a defrag.
Try 'Defraggler' from Piriform and run it manually from time to time, about 20 min on a 2TB disk.

My understanding is that consolidation of free space amounts to defragmenting the free space, IOW making it contiguous. There is definitely a point of diminishing returns there, and what seems to be lacking in the Microsoft program is an intelligent determination of where those diminishing returns begin, which I judged from watching the drive thrash for an hour to go from 5% to 9% after file defragmentation had been completed.

But yes, it looks like it's impossible to skip the free space consolidation. While the scheduled task uses the generic /O option, being more specific doesn't help:


While the file defragmentation completed instantly, it's now stuck in the free space step, and a smarter program would have called it a day given that 195 GB of the 298 GB free space is contiguous. What really sucks is that this is a freshly formatted drive restored from a backup using SyncBackSE and file-based copying. To add even more insult to injury, I Ctrl+C'd it after about 15 minutes this time and ran:


Note that the "Largest free space size" actually decreased, and the program stated that the volume doesn't need to be defragmented after it was perfectly happy to thrash my hard drive for what would have no doubt amounted to many hours had I not intervened. :facepalm: The only good thing I can say is that it seems to have gracefully handled the Ctrl+C interrupt, as it printed the following (but I'm still going to verify it against my backup):


So, this task is getting disabled. It would seem that it's actively harmful to drive health.