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Mounting external drives is SUPER slow

M

motrek

macrumors 68030
Original poster
Sep 14, 2012
2,635
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Hi guys, this has been annoying me for a while, finally decided to post about it.

I have a handful of external USB hard drives that I keep in a rotation and use for backing up some files. Each drive is formatted APFS, encrypted. At any point in time, each drive probably has around 300,000 files of varying sizes.

What's bugging me is that when I plug a drive in, it crunches for 1-2 minutes before even prompting me to decrypt the drive. Then I enter the correct password and the drive crunches for another 1-2 minutes before it shows up on the desktop.

This is kinda stupid. What is MacOS doing with these drives? Especially before I've entered my password, since theoretically the system can't even read or write anything to the drive?

I remember mounting an external drive used to only take a few seconds with older versions of MacOS. What's changed?

Anybody else see this behavior? Thanks in advance...
 
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Having this issue with one of my drives. Showing up in the system report as a connected USB device but won't mount for a few minutes most of the time.
 
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Taz Mangus said:
Try booting into Safe Mode and see if the drives still mount slow.
...
Click to expand...

Yup, just tested, it's slow either way.

Time to bring up password prompt, not in safe mode: 1 minute, 2 seconds
Time to show up on desktop, not in safe mode: 14 seconds

Time to bring up password prompt, safe mode: 42 seconds
Time to show up on desktop, safe mode: 29 seconds

So it's not really the 1-2 minutes that I originally said but it's still a hell of a long time to be reading and writing to/from a drive just to recognize that it's encrypted and a password prompt needs to be displayed.
 
Taz Mangus said:
If the drive is not encrypted does it also take a long time to mount?
Click to expand...

The drive is encrypted.

When I unmount it, it disappears from the desktop almost instantly.

But, I can still hear the drive crunch away for ~10 seconds after it disappears from the desktop, which is pretty s**tty but seems like a different problem.
 
motrek said:
The drive is encrypted.

When I unmount it, it disappears from the desktop almost instantly.

But, I can still hear the drive crunch away for ~10 seconds after it disappears from the desktop, which is pretty s**tty but seems like a different problem.
Click to expand...

I was asking you if you have tried mounting a non-encrypted drive to see if it takes a long time to mount.
 
Taz Mangus said:
I was asking you if you have tried mounting a non-encrypted drive to see if it takes a long time to mount.
Click to expand...

Interesting question but I don't have any drives that aren't encrypted. And I'm not going to format a drive just to check...
 
I recently started noticing similar issues as my external backup hard disk is filling (it's not really full, about 500 GB of a 2 TB drive are in use).

Also, if the backup drive is connected to the Mac at boot time, it slows down the startup quite noticeably.
 
I feel like they've made a big improvement with Monterey. Which version of macOS are you using?
 
ARMunix said:
I'm already on Monterey, M1 Mac mini.
Click to expand...

Nuts, no idea in that case.

To be clear, on my Intel iMac, mounting encrypted APFS drives still isn't fast, but at least it doesn't take over a minute...
 
Are you using FUSE? If yes, try updating to the newest version (may require some changes in security preferences to allow driver to be in use) and if that won't help, try removing.
 
Have had the same issue for awhile with my WD external HDD. I have 3 encrypted volumes (APFS Volume • APFS (Case-sensitive, Encrypted))and one unencrypted ExFAT volume. The ExFAT mounts immediately, the 3 other ones take their sweet time to pop up the password. They are not journaled, could that be the issue? It seems like this happened when I got a new HDD but don't recall exactly anymore.
 
rmn1644 said:
Have had the same issue for awhile with my WD external HDD. I have 3 encrypted volumes (APFS Volume • APFS (Case-sensitive, Encrypted))and one unencrypted ExFAT volume. The ExFAT mounts immediately, the 3 other ones take their sweet time to pop up the password. They are not journaled, could that be the issue? It seems like this happened when I got a new HDD but don't recall exactly anymore.
Click to expand...
It has been brought to my attention that APFS was never designed to be performant on a hard disk. Something about how it stores metadata all over the disk, which is not a problem for SSDs because random-access latency is so low, but it's a huge problem for hard drives. So maybe it wasn't that smart to reformat all my drives as APFS when it came out.

That being said, it still doesn't explain what the OS is doing when you plug the drive in. It should immediately recognize that the drive is encrypted and prompt for a password. How does it spend a minute crunching around on the drive when it theoretically isn't able to read any of the data on said drive?!
 
motrek said:
It has been brought to my attention that APFS was never designed to be performant on a hard disk. Something about how it stores metadata all over the disk, which is not a problem for SSDs because random-access latency is so low, but it's a huge problem for hard drives. So maybe it wasn't that smart to reformat all my drives as APFS when it came out.

That being said, it still doesn't explain what the OS is doing when you plug the drive in. It should immediately recognize that the drive is encrypted and prompt for a password. How does it spend a minute crunching around on the drive when it theoretically isn't able to read any of the data on said drive?!
Click to expand...
So whats the solution? What should we be formatting out external HDDs as?
 
rmn1644 said:
So whats the solution? What should we be formatting out external HDDs as?
Click to expand...
No idea. "Mac OS Extended," I guess? (Is that HFS?)

I don't think I'm going to bother. If I had to use my hard disks more often, I would probably reformat them. As is, I just back up my data once a week.
 
I actually have a really similar problem with my TimeMachine HDD, it will getting slower and slower from week to week.

Currently I using a Lacie Rugged USB-C 4TB external HDD for my TimeMachine Backups. The TimeMachine disk is formatted to APFS encrypted (the time machine setup looks like can only format in APFS and I think doing backups makes only encrypted sense).
So every thing went well for some weeks even months but from time to time the mounting will go slower and slower. Means it takes 20-30 seconds to display the password prompt and afterwards it takes again more than 1 minute to mount that disk so that TimeMachine can start with doing the incremental backup.
Right now the disk is used around 800GB and it feels with every GB the mounting is getting slower.

I have no idea why that is a problem and even buying a SSD for a TimeMachine backup doesn't makes sense to me. Maybe someone knows how to speed up, because it looks to me APFS disks without encryption are mounting much faster (I tried it with an another Lacie Rugged USB-C) but doing backups without any encryption isn't option.
I also tough about to move to HFS+ with encryption but the TimeMachine setup process only allows under macOS 13.3 APFS.
 
greenchapter said:
I actually have a really similar problem with my TimeMachine HDD, it will getting slower and slower from week to week.

Currently I using a Lacie Rugged USB-C 4TB external HDD for my TimeMachine Backups. The TimeMachine disk is formatted to APFS encrypted (the time machine setup looks like can only format in APFS and I think doing backups makes only encrypted sense).
So every thing went well for some weeks even months but from time to time the mounting will go slower and slower. Means it takes 20-30 seconds to display the password prompt and afterwards it takes again more than 1 minute to mount that disk so that TimeMachine can start with doing the incremental backup.
Right now the disk is used around 800GB and it feels with every GB the mounting is getting slower.

I have no idea why that is a problem and even buying a SSD for a TimeMachine backup doesn't makes sense to me. Maybe someone knows how to speed up, because it looks to me APFS disks without encryption are mounting much faster (I tried it with an another Lacie Rugged USB-C) but doing backups without any encryption isn't option.
I also tough about to move to HFS+ with encryption but the TimeMachine setup process only allows under macOS 13.3 APFS.
Click to expand...
I recently learned that we can use a sparse disk image bundle for time machine backups. Changed my life.
 
greenchapter said:
...
I have no idea why that is a problem and even buying a SSD for a TimeMachine backup doesn't makes sense to me. ...
Click to expand...
Dunno how to solve your Time Machine problem but realize that data rot is a problem with SSDs so maybe buying an SSD to do backups isn't the best idea anyway.

I believe SSDs are supposed to reliably store data, unplugged, for a year, but any longer than that and you're risking data corruption. I imagine you plug in (and use) your Time Machine drive more often than once per year but this is something I'd prefer to not worry about at all with my backup drives.
 
It's taking forever for my WD elements 2tb on ExFat just to mount, it's like more than 15mins. Fact is Mac OS sucks when it comes to external drives, at least for me at the moment on this so called M1 Pro MacBook Pro having Ventura 13.4.1 OS. Moving back to Windows where life was easier, regretting about my investment :(.
 
I'm sound engineer and on live events artists bring me lots of usb to plug and copy their music file to my macbook pro.
Every single of them mounting time is around 2-5 minutes, but just the first time. If I remove the USB and plug it in again, it mounts in few seconds. So I believe there is some verification process going on in the background cause after "verification" the usb mounts fast. Most of the USB flash drives is FAT32.

I found similar problem solution for LINUX here: https://forums.linuxmint.com/viewtopic.php?t=219880
But not sure if it would help for MacOS users. But maybe it will be a hint about what is going on with this problem and clever man will arise here 😁

About my macbook pro:
13", Mid 2012
Procesor 2.5 Ghz Dual-Core Intel Core i5
Memory 8 GB 1600 MHz DDR3
Graphics Intel HD Graphics 4000 1536 MB
macOS Catalina 10.15.7
Storage: SSD 120 GB
 
I had a login script that would wait 10 minutes for my six (6) external, encrypted, APFS drives to mount. The day came when the script would timeout before all drives were mounted. Read this thread and others. Bought a 7th drive so that I could re-format 5 APFS HDDs to HFS+. Kept the 1 external SSD as APFS. So, now I have 1 extra drive than before. 6 HDD's as HFS+ unencrypted, and 1 SSD as APFS. Mount time went from 10 mins / Not At All, down to 17 seconds!
 
motrek said:
Hi guys, this has been annoying me for a while, finally decided to post about it.

I have a handful of external USB hard drives that I keep in a rotation and use for backing up some files. Each drive is formatted APFS, encrypted. At any point in time, each drive probably has around 300,000 files of varying sizes.

What's bugging me is that when I plug a drive in, it crunches for 1-2 minutes before even prompting me to decrypt the drive. Then I enter the correct password and the drive crunches for another 1-2 minutes before it shows up on the desktop.

This is kinda stupid. What is MacOS doing with these drives? Especially before I've entered my password, since theoretically the system can't even read or write anything to the drive?

I remember mounting an external drive used to only take a few seconds with older versions of MacOS. What's changed?

Anybody else see this behavior? Thanks in advance...
Click to expand...
Hello all,
i had this issue after updating to Sonoma, my WD 6TB external drive took almost 3 minutes to appear after plugging in.
the fix is very simple just activate hidden files (CMD+Shift+ . ) and delete (CMD+Option+Delete) all of the hidden files and folders except your personal data. then eject the drive wait for it (it might stop and start twice) to completely eject.if it has adaptor turn it off remove the USB, restart your mac and done.
Rock on \m/
 
This has been bugging me, too, and so far I think it is mainly a combination of two things.

First, APFS does a huge number of random reads. This is why it simply does not work on spinning disks which have terrible random read performance. It turns out that a lot of external SSDs in general and "flash drives" in particular have really crappy random read performance for technology reasons I will not go into. (Technically there is no such thing as sequential reads on a SSD, yet performance tests show a difference. Please, no flame wars about whether it is really about random reads vs IOPS vs queue depth vs small block reads vs internal cache and predictive read-ahead vs something else.) So, point 1, even though my SanDisk Extreme Pro has great read speed, it kind of sucks at the APFS-intensive random read performance.

Second, this is amplified by APFS Snapshots. Time Machine and Carbon Copy Cloner use Snapshots to save old versions of files in a space-efficient way. (Maybe other applications use Snapshots, too, I just don't know of any.) However, they add complexity to file system, and if you run Disk Utility's First Aid, you will see they take a long time to verify, and again, they make heavy use of random reads. I suspect that the delay in showing the password prompt is due to doing a file system check prior to decrypting, and the delay after is from doing another file system check on the decrypted file system after decrypting.

You can test these theories by comparing load times with random access read performance on benchmarks, and by comparing load times with a lot of snapshots vs after deleting all those snapshots.

FWIW, I had similar complaints about mounting my internal drive after booting into Recovery mode on my Intel MacBook Pro. I now think it was because of the Snapshots.
 
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