iMac Storage

Yes, MS Windows is more of a storage user that Mac OS has ever been. Your issue is not with the amount of storage your iMac has or Mac OS itself, it is with your management of the storage you have.

Consider moving large libraries such as:

• photos
• music
• movies

to an external HD. You can do that with the 3 libraries noted above, the process is the same for each. To do so, Apple explains how for the photos in Move your Photos library to save space on your Mac

Welcome, kritharthshetty, to Apple Support Communities!

The principle cause of your “mysterious” Storage usage is the Storage Category called “Other”.

Fortunately, with newer versions of both macOS an iPadOS (perhaps iOS as well, but I don’t have any such devices, these days), the principle portion of this Storage Category is now labeled as “System Data”.

This is a far more appropriate label, for the principle data involved: System Logs, and other temporary files that your system uses to perform its functions.

(There may still be cases where User files, including App specific files, may go, temporarily, unrecognized under their more appropriate Storage Categories. I have seen cases where, given a bit of time, the “Other” Category has shrunk, while other Storage Categories grow, accordingly.)

One culprit for “Other” (or “System Data”) size can be Time Machine “snapshots” that are stored locally, before they are “archived” on your Time Machine drive.

Do you have Time Machine turned on?

Do you have an external Time Machine drive?

Show us a screenshot of your storage report:

See used and available storage space on your Mac - Apple Support