Hard drive filling up with Other. Hard drive / storage full

See the article What's in Others in your iCloud storage - Apple Support

Click on apple logo > about this Mac > storage > manage > others these data is encrypted , you can delete only caches and cookies contents from user library .

However if , iCloud data is to be reduced see some articles .

Manage your iCloud storage - Apple Support

Save space on your MacBook Air - Apple Support

How to free up storage space on your Mac - Apple Support

Find and delete files on your Mac - Apple Support

yannick chastang wrote: ..... One most annoying thing I have learnt in the past: the iCloud is often defaulting to “optimise Mac Storage (the full contents of iCloud Drive will be stored on this Mac if you have enough space”. I was clever this time and unticked the "optimise Mac Storage". I have done that on all my three computers.

If you disable "Optimise Mac Storage" all your cloud documents will be mirrored on your Mac as shadow copies and not just a few; you will not be saving any storage on your Mac at all. All documents will be in both place - in iCloud and on your Mac. It is essential to keep the option "Optimise Mac Storage" enabled, if you want to save storage by using iCloud. Then iCloud will only store as many documents locally, as space permits and remove shadow copies of documents, when you are low on storage.

... My iMac with Big Sur, up to date has 1TB hard drive. It was filling up slowly and I decided to turn off iCloud. It is now stable and not filling up over night. I have 793gb of "other" on the hard drive, and only 80GB of recognisable data / documents / utilities/ system.

1- What is that "other"?

2- How can I remove it?

3- Is it coming from iCloud and how can I stop that happening, and why?

Many thanks for your help,

Best regards,

Yannick

The link posted by tygb is explaining "Other" on an iPhone or iPad. For "Others" on a Mac see the user guide: See used and available storage space on your Mac - Apple Support

"Other" is completely managed by the system and you cannot control it or remove it.

• Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files and other runtime system resources. Also included are temporary files, fonts, app support files and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.

The system should automatically remove "Other" items, if you are running low on storage. on my Mac with 2TB storage the other is frequently growing up to 500GB, but on my Mac with only 250GB the amount of "other" used by the system is much smaller, only 80GB. It is containing mostly the local shadow copies of the files on iCloud Drive.

See the thread https://discussions.apple.com/thread/251789307

When iCloud Drive is turned as on and desktops and documents box is checked the iCloud data will start syncing between Macs when they are signed in with same Apple ID and password on the same network .

In old Mac if its not connecting to iCloud upgrade it macOS - How to Upgrade - Apple