iCloud won't stop dumping files on my MacBook Pro

I’m using a MacBook Pro with 1TB of internal storage, and I currently have about 4.5TB of data stored in iCloud under a 6TB plan. A month ago, I suddenly started getting alerts that I was running out of disk space. Within hours, my machine was down to just 100MB of free space. I couldn’t open Photoshop, Premiere Pro was completely unusable, and I couldn’t even save a small vector file in Illustrator. I was stunned—how was this even possible?

I started offloading everything I could—pushing files to iCloud or my external SSD, removing them from the computer. I got it down to just 60GB of documents. But then, a few hours later, the system filled right back up. And weirdly, I wasn’t seeing any new files appear. It made no sense.

I dug deeper and noticed that “System Data” had ballooned to nearly 800GB. I contacted Apple Support and spoke with multiple associates over several calls. Everyone was friendly and tried to help—clearing caches, deleting unused apps—but I kept repeating: That’s not the issue. One rep finally suggested removing iCloud Drive from the device. I hesitated, because I rely on that seamless Finder integration. But eventually, I tried it out of desperation.

Now I’ve got over 650GB of space back. But I lost the one thing that made iCloud actually useful to me: native access to my files. iCloud.com is not a viable alternative—it doesn’t even support file searching properly. And with 4.5TB of data, that’s just not manageable.

This behavior is new. I’ve had iCloud Drive on my Mac for years without this issue. The system used to intelligently offload files when needed. Now, it appears to be force-downloading huge volumes of data and treating them as unremovable “System Data.” According to Apple:

“The full contents of iCloud Drive will be stored on this Mac if you have enough space. Older documents will be stored only in iCloud when space is needed.”

But that’s not what’s happening. I don’t have enough space—and it’s still trying to pull down everything. Why? What changed? Has anyone else experienced this?

I just want iCloud to act like cloud storage again—keeping my files available when I need them, without hijacking my entire hard drive. That’s the point, right?

[Re-Titled by Moderator]

Original Title: iCloud won't stop dumping files on my computer.