External Hard Drive incredibly slow after High Sierra

Apple do not recommend APFS for HDD disks, for this very reason.

Hello J4MMYz,

It sounds like you have some other software conflict. No one can speculate about what may or may not have been the issue with your external hard drive since you have converted it to APFS. If you do not already have a backup of this disk on HFS+, I strongly urge you do drop whatever else you might be doing and make that backup right now.

J4MMYz wrote:

Thats a joy, Time Capsule filled up yesterday, for some reason unknown to me I decided to wipe it and order a new HDD which comes Friday. Thats whats concerning me now as I do not have a backup so if something goes wrong im done for.

What is the best course of action? Hopefully Apple will have a fix for this?

The best course of action is to stop posting on the internet, drive to the nearest place where you can buy an external hard drive, and back up all of your data. Time Capsule is a nice convenience when it is working properly, but there is no substitute for a good backup drive.

No, Apple is not going to fix your 3rd party hard drive.

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.

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).

CONFIRMED

I have the same issues. Plugging in any of several external WD gig+ drives make High Sierra slow to an intolerable speed (and we are talking maybe 40 minutes to move a file speed). Take the same drives and plug them into Sierra, El Capitan, life is fine... everything runs as expected.

I have two desktops running High Sierra, and both won't budge once there is an external drive plugged in. Drive health on all computers and external devices is excellent.

Absolute nightmare! I don't want to be using beta but yeah, Apple has left no options if I want to have an external hard drive work. Everything good with the newest beta release.

Also skimming through this thread of extraordinarily arrogant responses blaming virus programs, hdd failure etc. Just wow

Hello I'm on iMac (Retina 5K, 27-inch, Late 2015), after the installation of high sierra, external HDDs that contains files with custom icons load their icons incredibly slow. About 1 icon every 20 seconds (which means 233 minutes in my case). I have hundred of files. While icons are loading iconservicesagent uses 35% (sometimes 160%-190%) of the CPU (so 4 hours of wasted CPU energy and usage slowing down other important mac processes). Every time I restart the mac the icons need to be loaded again. I've read this post but I don't really think that the solution is to delete the icons... instead Apple should support us and fix the problem. The reason why we use icons is to recognise files faster and easier (thanks S.J.). Hopefully Apple didn't change its point of view about that philosophy?

Apple did already fix the issue as mentioned before. I'm actually surprised they listened to the complaints and reacted so quick so credit to them. But if you don't want to get the beta you'll just have to wait for the newest High Sierra update

I have investigated a similar problem. What I found(can be replicated easily) is the presence of large mkv files.

On a mounted disk the problem does appear as soon as you open in the finder the folder containing the mkv.

On AFP or SMB shared folders, the problem is even worse as it comes every time you mount the folder.

If you have a dozen of large mkv, the mac will use all your network bandwidth until it has read each file completely (100GB of network trafic if you have five 20GB) mkv then become usable again.

you then unmount the network shared folder and mount it again, and high sierra kernel will start again to overload your network as before. It doesn't remember anything.

The worst system update I ever got with apple so far. (I'm only using apple hardware since the apple ][ and I've brought over 30 macs over the time) and now that Apple make it very difficult to go back to the previous os version, it's really a nightmare.

This is exactly what I'm experiencing. I use movie poster jpegs for custom icons on all my movie files. After OS update my external drives (three separate drives with movie files) take forever to load. Is there a way to delete all custom icons at once. I won't do hundreds of files one at a time! BTW, my icons now load as a square stretched copy of original jpeg. Nov. 19, is there a fix yet? Oh yeah, I almost forgot, on some files it says something like "verifying file" before it opens. It's without a doubt High Sierra.

It's definitely a bug with the custom thumbnails. I even tried cropping the photo (which is something I never used to need to do) and it still appeared square and stretched. When I made my initial bug report, I included both issues (the thumbnail issue and the slow loading time) and know others here mentioned both in their reports as well. It's one of those things that should be an incredibly easy fix.