High Band With "idleassetsd" & "nsurlsessiond" back ground process

I had this issue on Sonoma. I used some basic methods to see the unencrypted content, and it was due to screen savers/wallpapers. The thing is, I clicked on them and ultimately did not use them, so it would seem that it triggered a background download of a ton of large high-def video files, regardless of the fact that they are no longer selected (and they continue to download). It doesn't bother me, as it seems to throttle itself down when other traffic starts to show up, so I haven't noticed any slowdown. I can see the video files consuming hard disk space (I took a snapshot, let it sit, took another, and compared the difference (please don't tell me that there are a million better ways of doing that. I was doing it for another issue primarily).

Edit:

I found a SQLite database of what it is downloading. However, I wouldn't mess with that without talking to Apple Support first.

You can run lsof if you are comfortable with the terminal. Here is what mine showed:

user@computer ~ % lsof | grep -i idle
Wallpaper   581 user    4r      REG                1,4  481292429             5366651 /Library/Application Support/com.apple.idleassetsd/Customer/4KSDR240FPS/097CA871-A1C2-40F7-97F0-EFAABF555BBC.mov

If you prefer using a GUI, there is a great free program that basically visualizes the lsof output. The utility is Sloth.

Note that it takes "snapshots" and is not a monitor (although you can have it refresh at certain intervals).

Output From Sloth:

Note that in both cases, the output can be very large, which is why I used "grep -i idle" and searched in Sloth (I highlighted the search box in the top right).

I would not recommend blocking this connection in any way. The OS uses this to download many things. I would figure out exactly what it is downloading and work from there. Otherwise, you may have issues in the future when the OS is trying to download something that you do want, but it is blocked. Additionally, it will continue to try to connect and download and continue to fail, which would be undesirable.

I ran into this issue as well as idleassetsd in my activity monitor was using 50GB/hr that led to over 700GB usage per day.

I contacted Apple Support and they recommended setting Wallpapers and Screensavers to a static image.

After restarting Activity Monitor idleassetsd stopped downloading as it is now at 0 bytes sent and recieved.

I had this exact same issue. Disabling animated wallpapers solves it immediately. So unless you desperately want animated wallpaper/screensaver, the easy fix is just disabling them. Clearly a bug in the system though, no way it should require such a massive amount of downloads.

Yes this worked for me today under Sequoia OS 15.1. First I had only done Wallpaper, but you must set BOTH Wallpaper AND Screensaver to a static image.

idleassetsd connecting to sylvan.apple.com might be what has been causing my rural 4Mbit DSL download speed to land in the crater recently. I've been trying to uncover what has caused my household bandwidth to sink to 1 and 2Mbit download speeds.

I have Little Snitch (ObjectiveDevelopment) firewall (highly recommend - not in Apple Store) and took a look at what's using my bandwidth.

I blocked downloads from sylvan.apple.com specifically. Screen grab attached: for some time (how long ?) idleassetsd has pulled down 126GBytes from sylvan.apple.com. For comparison, the process nsurlsessiond has only done 5GB).

I don't know what idleassetsd is doing but since blocking it my DSL speeds are back to their crumby usual self.

However, the blocked requests look like about 1,000 requests PER SECOND, and it is at the top of my %CPU usage in Monitor. Killing process, it comes back in a second. Problem not solved yet but this may have been what is draining my DSL bandwidth; I have spent hours with Brightspeed (Centurylink) tech support trying to solve / complain the poor connectivity. This seems to be recent, or it comes in fits and spurts.

Setting static wallpaper and screensaver and then rebooting did not make any difference

Wiping /Library/Application Support/com.apple.idleassetsd (eg sudo killall idleassetsd; sudo rm -r "/Library/Application Support/com.apple.idleassetsd") seems to have worked so far

You need to set BOTH Wallpaper AND Screensaver to a static image

I've found that it might work if Low data mode is turned on while on a specific WLAN.

Wi-Fi settings > right-click the connected network > Network Settings... > Low data mode > restart wifi

Reference: https://apple.stackexchange.com/questions/461119/unable-to-stop-process-idleassetsd-from-consuming-infinite-bandwidth-on-macos

Circling back to my original post, "At some point, I might get to transport the MacMini to a place with Google Fiber and let it download to its heart's content. "

So I got the MacMini moved to fast internet, in LittleSnitch firewall I allowed sylvan.apple.com access from idleassetsd, and let it rip. And it did. I checked back in less than an hour and idleassetsd process quit downloading, and the usage reported from LittleSnitch progressed from 124GB total to 132GB.

As Roos_Cr reported, there is not a solution for rural DSL-connected customers (in my case, even 0.5MBit download burden did cripple the entire home DSL bandwidth). And 10's of GBytes forced download is NOT OK for folks with data/usage rate caps.

It was likewise a time-sink of hours with DSL tech support (Brightspeed), and an embarrassment while I insisted with the DSL provider it was all their lines being the problem: "you seem to have high usage, are there other devices connected?" (Well, they are hopeless at 4Mbit/512kbit in best-case). Adding insult to crap, their further excuse for poor services: "all my neighbor and my copper lines feed through one box" and if my neighbors are "using internet a lot" it could degrade my service. (hunh?)

My remedy now is to know this: when I transport my MacMini to a fiber place (in a town far away) to install MacOS upgrades, I have to let the machine sit operating for some hours to download in the background what was NOT downloaded as part of the install by idleassetsd.

On MacOS, I could finally divine the cause with LittleSnitch. On my laptop machine, I left it running long enough it finished its epic download. On the Apple TV, I have no such diagnostic tools, and idleassetsd is a TVos thing too.

Here is one more piece of information, after I searched Apple support for idelassetsd, I got this

Use Apple products on enterprise networks - Apple Support

it says:

Apps and additional content

Apple devices need access to the following hosts and domains for installing and updating apps, using certain app features, and downloading additional content. Some additional content might also be hosted on third-party content distribution networks.

Hosts: sylvan.apple.com

Ports: 80, 433

Protocol: TCP

OS: tvOS and macOS

Description: Aerial screen savers and wallpaper

Supports proxies: —

I also played with LittleSnitch firewall to see the effect on Activity Monitor CPU %, and real-time network traffic (reported for process by LittleSnitch) when I block and unblock network access for idleassetsd.

Blocked: about 1,000 "network access requests denied" per second, CPU % usage goes to about 150% and system heats up, and network download is reduced by about 500KBytes/sec.

Allowed: one "network access requests allowed", CPU % usage goes to about 2% and system cools off, and network download is runs continuously at a rate of additional 500KBytes/sec over whatever else is going on.

Network upload traffic is negligible compared to download traffic.

Again, this is on Sonoma 14.4.1 on an old Mac mini (2018) on a rural DSL line that only achieves (at best) 4MBits/sec download and 512Kbits upload speed (often worse - Thanks to Brightspeed/Centurylink for never replacing the buried copper-pair POTS lines since they were put in).

At some point, I might get to transport the MacMini to a place with Google Fiber and let it download to its heart's content. Maybe I only have another 50GB of animated screen savers and backgrounds remaining to be downloaded, and it will be finished with me and this episode will end. Apple, you have a demand-hog failure with idelassetsd (150% usage thread and 1,000 network requests per second makes my system glitchy - how about backing that off to 1 network check per five seconds for this NON-ESSENTIAL daemon task?).

Instead of adding a firewall app like LuLu, you can stop idleassetsd communicating with sylvan.apple.com by adding the following entry to the /etc/hosts file (as root or with sudo)

# workaround for idleassets bandwidth consumption
127.0.0.1             sylvan.apple.com

I was able to get it to stop by setting the Sonoma screen saver. This is right below the wallpapers section. Im also using a static wallpaper. Before this I was using a little snitch to block idleassetd but that'll slowly then eat up memory. I seen it go high as 30gb.

Overall Apple L. Stop doing this BS. I wasted more than 40 gigs from metered connection.