External Hard Drive incredibly slow after High Sierra

Not yet, good idea. Where do I file the bug report?

I tried removing my custom icons but when I tried it on a larger file my Mac just stopped responding and honestly I don’t have the patience to wait 10 minutes for a stupid icon to load just so that I can remove it.

I hope it won’t take them a year to fix this that’s just unacceptable.

All my movies and TV shows on my external hard drive are pretty much unwatchable right now.

I have the same question and have been looking for an answer to this since I upgraded to High Sierra on Tuesday. I have one USB drive connected directly to the iMac (2013) and another one as a network USB drive behind my router. Prior to the High Sierra upgrade, files on these drives were accessible nearly instantly. Now, for the most part, it takes over 60 seconds of "verifying" before the file opens. The identical files on the iMac hard drive open immediately as before. I am not hearing any unusual drive noise from either of these external drives.

I am completely certain this is not a coincidence.

Prior to this High Sierra update Tuesday, I have never before seen this popup that a file I'm trying to open is "verifying".

You are not alone on this, I am having the exact same problem with my Toshiba HD. It also happened before when I updated my Mac to Sierra so I just waited and after few months it started working again. It is happening now with my High Sierra update. So I would suggest just wait a while it might be some bug and Apple might fix it hopefully (finger crossed). Meanwhile if you come across any solution please do update.

I'm also having this $$%ˆ#$*&ˆ! problem with my macbook and seagate backup slim, after Mac High Sierra update.

Just try to access some folder on external HDD after a reboot or power on, BANG! 100% cpu, kernel_task ruin everything...

HDDs fail constantly, and at random times. It may be coincidental with your install of High Sierra, but it's still as likely as anything. Don't discount: test and discover. As usual, science is the only light in the darkness.

Data point: I have 3 large drives connected to different High Sierra Macs. No issues at all, FWIW.

I also don't trust spinning hard drives any further than I can throw them, and assume that any of them can go belly-up at any time with no warning. And sometimes, they do.

Odd. I'll be curious to see what it's all about, I am aware of no one else that has the issue outside of this discussion thread. Likely something a tad esoteric that doesn't appear in test matricies.

I never, ever use custom icons, so that might be factor. Dunno. We'll see.

Hi,

Thanks for bringing this up, I'm having serious iconsrviceagent issues.

I'm on a 2012 Mac Pro, High Sierra Os on SSD plus three internal HDD's. My main HDD holds my music and movies (with custom icons). My iconsrviceagent has been ramping up to 20 gigs of memory causing serious freezes/ slowdowns.

At this point after reading the comments, I ejected said HDD and everything is fine. Something's definitely going on. Either the icons, or some issues between APFS (SSD) and Mac Journaled (HDD's).

After the upgrade to High Sierra, whenever I access files on external hard drive, MacBook almost freezes for few minutes. This had happened before I moved the external drive to APFS, and I thought moving it will solve the problem, but it didn't.

When my external HDD is not connected, MacBook runs with no problems

So I had this same exact issue with my external hard drive and 2016 MacBook Pro running on High Sierra and was able to fix the problem.

For several days I was unable to even view the hard drive in Finder without the computer freezing up completely. After seeing that kernal_task and an iconservicesagent process were using the entire CPU when trying to access the drive, I knew it had to be an issue with the custom icons I had on several files and folders across the drive.

To fix the issue, I used my brother's MacBook Pro (still running Sierra where the hard drive could be used just fine) to delete all of the custom icons across the drive. Once all of the custom icons were removed from the drive, I plugged it back into my MacBook Pro running on High Sierra and the drive was immediately accessible and running perfectly.

This is definitely a weird bug where having custom icons on a large amount of folders/files across an external hard drive causes the computer to overload the CPU with an iconservices task. Hopefully Apple realizes this issue in the near future and releases a fix.

Thanks for everybody who posted to indicate the problem was tied to custom icons on large (e.g. video) files. I had dozens of large video files and also folders with custom icons.

Here is the solution I used, after which iconservicesagent is showing only high compressed memory usage and computer is otherwise running smoothly.

First, make sure you have developer utilities installed. To check, open a Terminal window and type: setfile. If the utilities are not installed, macOS will prompt you to install them for you, which is a 2-minute automated process. If setfile spits out its usage syntax, then it is installed and you can proceed.

At this point you can plug in your external drive. As soon as it gets mounted (before iconservicesagent takes all the memory!), in the Terminal window, cd over to the top directory on your drive under which your offending files reside. Then use one of the following, depending on how you want to identify the files from which to remove the custom icon:

$ find . -name *.mkv -print -exec setfile -a c {} \;

(i.e. remove the custom icon from all .mkv files below this point; use a different file name pattern as needed, e.g. *.avi)

$ find . -size +1G -print -exec setfile -a c {} \;

(i.e. remove the custom icon from all files 1 GB or larger below this point; adjust the minimum size as needed, e.g. +100M etc)

As I also had custom icons on many folders, I removed them all with:

$ find . -name Icon$'\r' -delete

The -print option in the above is merely to see which files are found and modified. It can be omitted.

I hope this works for others. I'd be curious to hear back.