MacOS fails with file operations on Desktop

Some more updates:

• What didn't work:

1. Running in safe mode
2. Reinstalling Tahoe

• What worked:

1. Creating another admin user, I didn't face the issues in that user account.

I really would like to preserve my original user as there are a lot of user-specific configs I rather not lose.

New issues encountered:

1. When I click on Apple ID in settings, it does not show the settings associated with Apple ID. Apple ID isn't grayed-out either, which is a common happenstance. All other items in the sidebar are clickable and they show their associated settings window, except Apple ID
2. I would try to click on Upload File for the same website, and the app would become non-responsive, both for Safari and Google Chrome. So this isn't app specific.
3. Occasional crash reports arise for Apple service specific services.
4. Some of my email folders for iCloud email, having always been there, don't appear under Mail app. When I go onto icloud.com and open Mail window, the email folders are there.

I believe this is an OS and/or iCloud related problem, might need Apple-backed support

My bad. It's mac mini with M4, running on Tahoe 26.1. Reboot and shutting down didn't help, neither did safe mode. Again, opening/renaming/moving/copying/deleting are not possible in Desktop and Documents, which I believe are tied to the cloud. I am able to do these with files in Downloads.

I don't think it's the cause, but I also checked the permissions for files, and I have read & write permissions. This is more wider than individual files

Paid for EtreCheck and even then the errors it found doesn't correspond to my problem (Heavy RAM/CPU usage). One more thing I noticed is that I would try to do a "File Upload" in a website on Google Chrome, and clicking file upload itself makes the browser a non-responsive application. I believe there's a certain issue with system dialog pop ups.

SamsungMagician is something I rather installed today, the issues pre-existed the software. I don't think any of these above addresses the problem. I will add a seperate reply with some updates as to what I tried

@D.I. Johnson & @Matti , I attached the etre check report, let me know if it helps! Looking forward to your response!

[Edited by Moderator]

Thread Title: [SOLVED] File Upload Dialogs Crashing, Apple ID Settings Frozen & Finder Locks (The iCloud Deadlock)

Post Content:

I finally fixed a critical issue that made my user profile almost unusable. I’m posting the solution here to save others the headache. Big props to Google Gemini for sticking with me through the deep-dive troubleshooting to find the root cause when standard fixes failed.

The Symptoms:

1. Upload Crashes: Clicking "Upload File" in Chrome/Safari would instantly crash the browser or beachball forever.
2. Settings Frozen: System Settings > Apple ID was unresponsive or showed "Application Not Responding."
3. Finder Locks: I couldn’t move, rename, or delete files in my Desktop or Documents folders.
4. The Clue: Everything worked fine in a New Admin User, and everything worked fine if I was Offline (Wi-Fi off). The moment I signed into iCloud, the system deadlocked.

The Root Cause:

This wasn't an OS issue or a Permissions/TCC issue. It was Data Corruption in the local CloudKit Group Containers (~/Library/Group Containers).

Specifically, the bird (iCloud Drive) and cloudd background processes were choking on a corrupted local database. When they tried to sync, they entered a "zombie" state, deadlocking the file system. Any app attempting to open a file dialog (which queries iCloud) would hang waiting for bird to respond.

The Solution (The "Surgical Deep Clean")

Warning: This resets your local iCloud cache. Your actual files on iCloud.com are safe, but local unsynced changes might be lost if you don't back them up manually.

Step 1: Go Offline (Critical)

• Turn OFF Wi-Fi and unplug Ethernet. You must sever the connection to stop the background processes from auto-restarting and locking the files.

Step 2: The Terminal Fix

Open Terminal and run these commands in order:

• Kill the frozen processes:

killall -9 accountsd bird cloudd "System Settings"

• Quarantine your local Mobile Documents folder: (We rename it instead of deleting it to avoid "Resource Busy" hangs).

sudo mv ~/Library/Mobile\ Documents ~/Library/Mobile_Documents_Old

• Nuke the Corrupted CloudKit Engines: (This forces macOS to generate fresh sync databases from scratch).

rm -rf ~/Library/Group\ Containers/group.com.apple.cloudd
rm -rf ~/Library/Group\ Containers/group.com.apple.bird
rm -rf ~/Library/Group\ Containers/group.com.apple.iCloudDrive

• Reset Account State:

rm -rf ~/Library/Accounts

Step 3: The Restart

1. Reboot your Mac.
2. Log in (Keep Wi-Fi OFF).
3. Open TextEdit and press Cmd+O. If the window opens instantly, the deadlock is broken.
4. Turn Wi-Fi ON.
5. Go to System Settings and sign in to your Apple ID.
6. Wait 60 seconds for the system to rebuild the Group Containers.

After doing this, I re-enabled "Desktop & Documents" sync, and everything is working perfectly. No more crashes.

Hope this helps anyone else stuck in this iCloud loop!