macOS 26.1 – Severe lag in Open/Save panels when iCloud Drive root contains any items (FileProvider v3 regression)

I’ve filed this as FB20943098 (macOS 26.1 – FileProvider v3 synchronous enumeration bug), but posting here in case others can reproduce and add duplicates.

This is a known issue (r.161915582). While it isn't fixed in the current seed (macOS 26.2 25C5031i), the issue is a high priority that's being actively investigated.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

Awesome. I don't know if this will help, but I seem to have resolved the problem on my M4Pro Mini running these two commands:

# Quit apps that might use iCloud Drive
osascript -e 'tell application "Finder" to quit'

# Kill iCloud daemons
killall bird cloudd fileproviderd

# Remove local iCloud metadata cache (NOT your files)
rm -rf ~/Library/Application\ Support/CloudDocs
rm -rf ~/Library/Caches/CloudKit
rm -rf ~/Library/Caches/com.apple.CloudDocs
rm -rf ~/Library/Preferences/MobileMeAccounts.plist

# Restart the system
sudo shutdown -r now

and this one:

osascript -e 'tell application "Finder" to quit'
killall fileproviderd bird cloudd

# Move the offending FileProvider container aside
mv ~/Library/Application\ Support/FileProvider/723EBBFF-303E-471D-924D-C7D140F50B49 \
   ~/Library/Application\ Support/FileProvider/723EBBFF-303E-471D-924D-C7D140F50B49.old

# Let macOS rebuild a fresh one on reboot
sudo shutdown -r now

The strange thing is, my Macbook Air the same commands didn't do anything. There were two instances where I resolved the lag on my Air.

1. I removed a specific folder from the ROOT directory of my iCloud drive. Unfortunately the problem came back

2. I then took everything out of my drive (including desktop and documents), made a backup of it. Then screen shared into my M4 Mini and from that backup, restored it to documents on my Mini. Even after the Air was done syncing, it was perfect for a little bit.

3. Macbook Air, I deleted everything. Lag. Turned OFF desktop/documents. Lag.

I hope this MAYBE helps.

Awesome. I don't know if this will help, but I seem to have resolved the problem on my M4Pro Mini running these two commands:

Basically, yes, that all makes sense. The issue appears to be caused by the combination of:

1. Broken bookmark references that can't be resolved (this is common, given the data the panel is interacting with).

2. The failure in #1 triggering network/download activity.

3. Some... suboptimal behavior in the panel which is causing it to unnecessarily repeat the same work multiple times.

Note that #3 is the dominant factor, as repetition is what's ultimately creating the visible impact, not the individual operations. In any case, deleting/moving the "right" data bypasses the problem by avoiding #1.

However...

The strange thing is, my MacBook Air with the same commands didn't do anything. There were two instances where I resolved the lag on my Air.

...that exact data involved will vary from machine to machine.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

As a lifetime Windows only guy having my first Mac ever in my life after 35 years of running Windows (and hating Mac)

Not only is it supreme in hardware and software, but never have I had a response from an actual engineer. Not to mention a helpful and clear response.

Thank you sir, and for all your hard work.

...the issue is a high priority that's being actively investigated.

Following up on that, FB20943098 should be fixed as of macOS 26.2 beta 2 (25C5037j).

As a lifetime Windows-only guy having my first Mac ever in my life after 35 years of running Windows (and hating Mac),

Welcome to the party!

Not only is it supreme in hardware and software, but never have I had a response from an actual engineer. Not to mention a helpful and clear response.

Thank you, sir, and for all your hard work.

You're very welcome.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

100% confirmed working with 26.2 beta 2 (25C5037j) on MacBook Air M4 with 24GB RAM.

I barely even let it boot I was so excited to check. Amazing! Thank you so much!