storage space running low

"Other" includes that of the same category belonging to other users of that Mac—including files occupying space as you described in your other Discussion: Mac OS Recovery.

Assuming you were able to successfully delete that recalcitrant disk image (and empty the Trash), "Other" should now reflect a more reasonable amount.

Check for its presence in /Users/

A Mac with just one User Account will normally have that Account, plus one other folder named Shared. Investigate anything in addition to those.

First please review How to free up storage space on your Mac - Apple Support.

EtreCheck might help resolve discrepancies regarding used vs. free amount of disk space: ‎EtreCheck on the Mac App Store

Caveat: I have not encountered that problem (over half my hd is filled with "other") so I can't say whether it will help identify an excessive amount of the "other" storage category or not, but it's probably the easiest way to do that. Otherwise you need to use "Get Info" on that storage device, correlate its information with Disk Utility, resolve any discrepancies between it and About This Mac > Storage, and basically know in advance what you're looking for.

I don't see any screenshot either.

Unfortunately, EtreCheck from the Mac App Store will not help. EtreCheckPro will be able to help. It has a "Storage display" that will tell you where all of your storage is being used. It doesn't attempt to classify the storage in any way. It just shows you the allocation on disk. It will actively discourage you from accessing any directories where it might be unsafe to delete any files. EtreCheckPro may also give you a button that will delete your local snapshots.

Unfortunately, due to a recent change in the Apple Support Communities Use Agreement I can no longer post a link to EtreCheck or EtreCheckPro, because I am the author.

FYI, there is no screenshot for us to see. You need to use the second icon from the right to insert an image:

And, there is no Apple "staff" here - we are all other users. If you wish to contact Apple support, the link is in the upper right corner of this page.

However, most of us know what you are referring to. If you will click on "manage" in that window, it will give you a better idea what is stored where and you can control it.

And, we cannot definitively answer your question because there has been no information released by Apple that details exactly what "other" is. You could say it includes whatever is left after identifying the other categories and what they include which is not helpful. Also, that little bar with its colors is notorious for being inaccurate. Either use that second window to get a more precise list or download Omni Disksweeper to give you an exact list of what is on your computer.

Here is a copy and paste from the last time I answered this question 3 minutes ago...

The "System" storage are just files that the storage manager cannot properly categorize. It could be things like caches, swap files, or Time Machine local snapshots. (Note, you may have Time Machine local snapshots even if you aren't using Time Machine.)

In theory, the system is supposed to automatically delete all of those things if it runs out of space. In practice, that sometimes doesn't happen, or it happens a long time after you get the "out of storage" alert.

The operating system only reports "available" storage, which is why this shows up unexpectedly. That mystery 83 GB is actually your "available" storage which actually isn't "free" storage. If you run Disk Utility, it will show you actual "free" space for your hard drive, which will be much lower.

The only solution is to download a 3rd party storage management tool. Unfortunately, those tools often lead people into hidden directories where they can really scramble their system and lose valuable data. I only know of one such tool that clearly identifies which areas are safe for users to enter and delete files. It also gives you a handy button to delete local snapshots. Alas, it is my own tool so I can't post a link to it here in the forums. Bummer.

Note: I'm not complaining about you asking about. That's normal. It is the behaviour of the operating system that annoys me.

Sorry but this isn’t an answer.

No need to apologize. An answer requires more investigative work on your part. If you find my suggestions unhelpful you are welcome to seek others.

I even sent a screen shot ...

To whom?

What is all that undefined stuff?

Anything that is not Documents, Apps, Music, TV... etc.

It's not a question of smart enough. The Mac was attempting to save a deleted User Account in a disk image. That's a normal thing for it to do, but for some reason it failed.

Apparently the resulting disk image file was large. I surmise insufficient disk space contributed to the problem, but attempting to determine the exact reason probably isn't worth the effort.

Same problem