Cannot find or remove 100+GB of "Hidden Space

UPDATE: It worked! I successfully did a clean install of the new OS (I went from High Sierra to Mojave), and then migrated my data over from my Time Machine drive, and everything appears to be back in order.

So I guess that rules out Time Machine as the cause of the original problem...

Some final tidbits to wrap up, so that the next person down the line with this problem has as much ammo as possible;

1) I had a nearly impossible time making the Boot Drive for Mojave, as the expanding hidden file was taking up too much space for me to even download the Mojave installer (It's 5+ gigs, and the smaller version isn't the full installer, which is what is needed to do a clean install from a boot drive). Every time I deleted files to make space for it, the hidden file/space would just eat up the free space I had created before I could get the full Mojave install file on my disk. It ultimately took a few hours of tedious deleting each and every file from my hard drive and then trying to quickly download the Mojave installer file before the growing hidden file overtook the free space I had cleared. When I finally got it to work, I had deleted literally almost every single file from my computer, and only had 600mb or so free after the Install file finished. Unreal.

2) When I finally was able to reboot from the boot drive, I erased my entire hard disk via Disk Utility (as per instructions on how to do a clean install), but then when I attempted to install the new OS on my recently wiped drive, it said there wasn't enough space. Then I noticed this;

So somehow now the hidden file/space was coming up under "Other Volumes", where-as before when I had done Disk First Aid to try and repair things (multiple times, during multiple different attempted solutions), the space was showing up as in my hard disk (Macintosh HD). So...that's pretty weird. And I've never partitioned my disk, and don't have other users on my system etc., or anything that would explain how this could be.

This solution here thankfully worked for erasing the hidden data from the "Other Volumes" section of my hard disk, but it still makes no sense whatsoever how it got there in the first place. That said, at this point, I'm just grateful that after 4 days of endless attempts, I've finally been able to reclaim my computer from this monster.

I'm not enough of a computer person to understand if/how it would be possible, but it really seems like my computer was somehow either emptying my trash, or backing up my trashed files, to some sort've hidden partition or area on my disk for some reason. ¯\_(ツ)_/¯

So, just to wrap this up for anyone else who runs into this problem in the future and lands here as a result;

The only solution was to wipe the drive (make sure you backup all your data first, obviously), and do a clean install of the OS. Then import/migrate your data from your backup. Time Machine worked fine for me, but in case it doesn't, I made a manual backup of all my files as well on another drive, since I wasn't sure if whatever was causing this problem would be included in my latest Time Machine backup (thankful it wasn't).

Hopefully this helps other people who encounter this problem!

Sure thing. Was definitely to no fault of OmniDiskSweeper, nor was my inability to get anywhere with DaisyDisk it's fault - because the corrupted file or problem is/was somewhere hidden on my hard disk, but presumably not registering correctly as a file, there wasn't a way to identify where or what the large hidden file is.

As I delete larger files, the free space that should be clearing up just gets eaten by whatever is causing this problem (it's either that my computer is emptying it's trash somewhere else on the hard disk, or there's a corrupt time machine file that's backing up everything as it gets deleted to a hidden area. See examples below.

I'm ultimately going to just wipe my computer and start from scratch with a clean install of the new OS (that's the only actual solution I've seen work for others). Will follow-up here if it works, as It's been very frustrating to see how many other people have been having this problem without any actual solutions or causes being found.

Had no luck with OmniDiskSweeper unfortunately, but I hadn't checked Console -haven't ever used it to be honest- but found that there were a bunch of error logs.

Not sure what would constitute them being abnormal or huge, but a few that jumped out were;

process_snapshot_phys_extents:504: tree_iterator_init() on delta_tree (oid 870458) returned 92

default 20:31:22.113890 -0800 kernel find_next_non_dataless_snapshot:654: apfs: next = 356472 err = -1

default 20:31:22.118981 -0800 kernel nx_corruption_detected_int:58: Corruption detected by btree_node_val_range_validate:875 in container ECA262C2-6E3C-4587-A889-882971BC90BA!

default 20:31:22.118998 -0800 kernel process_snapshot_phys_extents:504: tree_iterator_init() on delta_tree (oid 870175) returned 92

default 20:31:22.119009 -0800 kernel delete_clone_fs:1656: Error processing blocks from snap xid 119812 into snap xid 356472, err 92

default 20:31:22.119032 -0800 kernel find_next_non_dataless_snapshot:654: apfs: next = 742453 err = -1

default 20:31:22.119078 -0800 kernel nx_corruption_detected_int:58: Corruption detected by btree_node_val_range_validate:875 in container ECA262C2-6E3C-4587-A889-882971BC90BA!

default 20:31:22.119088 -0800 kernel process_snapshot_phys_extents:504: tree_iterator_init() on delta_tree (oid 883958) returned 92

default 20:31:22.119098 -0800 kernel delete_clone_fs:1656: Error processing blocks from snap xid 356472 into snap xid 742453, err 92

default 20:31:22.119116 -0800 kernel find_next_non_dataless_snapshot:654: apfs: next = 817767 err = -1

default 20:31:22.119157 -0800 kernel nx_corruption_detected_int:58: Corruption detected by btree_node_val_range_validate:875 in container ECA262C2-6E3C-4587-A889-882971BC90BA!

default 20:31:22.119167 -0800 kernel process_snapshot_phys_extents:504: tree_iterator_init() on delta_tree (oid 1011107) returned 92

default 20:31:22.119177 -0800 kernel delete_clone_fs:1656: Error processing blocks from snap xid 742453 into snap xid 817767, err 92

default 20:31:23.521948 -0800 sharingd Nearby stop advertising of type: 16

default 20:31:23.522109 -0800 sharingd Nearby start advertising with data: Advertising request of type 16, priority 1, UseFG 432 (270.00 ms), data <0b00>, connectable 1, options {

} priority 0 mode 432 options (null)

Appreciate the follow-up, however I've already tried the solutions offered in both of those posts, and neither has worked. I got rid of an old dateless snapshot the first time I did it, and have deleted the current snapshot that my computer seems to be making (it's dated as today's date) in it's place each time after.

Even after doing this, I still get the same error when I run Disk First Aid, and still have the same problem with the hard disk space....

Could it be that there's a hidden snapshot or hidden time machine file somewhere on my computer that I can't access or find? That's what seems to be the most likely scenario (or some sort of error / corrupted file that maybe happened when I setup a new Time Machine several months ago?). If that was the case, what would my next steps be to find/delete/solve a hidden/corrupted snapshot / backup?

I'm getting pretty close to just wiping the drive and doing a clean install of Mojave, but I worry that when I import all of my data from Time Machine, it'll include the hidden/corrupted file... Thoughts?

I did search for hidden logs, as well as hidden caches or containers, as that had been the culprit for some people, but alas, was not for me. Appreciate the suggestion though. I'm gonna try an clean installs of the new OS and see if I can migrate my date over from Time Machine that way, and if not, I've got a manual backup as well that I'll try after. Will update here if either work!

What're you talking about? I clearly laid out a straight to the point action plan (twice in fact!).

Perhaps you did not read the entire post (it's long, I know), but the very first sentence stated that the only thing that worked was wiping the drive and performing a clean install of the OS.

And the very end of the post gave direct instructions on what to do;

"So, just to wrap this up for anyone else who runs into this problem in the future and lands here as a result;

The only solution was to wipe the drive (make sure you backup all your data first, obviously), and do a clean install of the OS. Then import/migrate your data from your backup. Time Machine worked fine for me, but in case it doesn't, I made a manual backup of all my files as well on another drive, since I wasn't sure if whatever was causing this problem would be included in my latest Time Machine backup (thankful it wasn't)."

Thanks for trying to help me and for following up here!

And thanks to everyone who tried to help solve this!