External HD slow to mount every time I boot up Mac

I updated to 14.5 and mines started mounting right away now so I’m safe to say the update fix that issue.

Hi.

I am facing similar issue with exFat drive on Sonoma AND Mac Studio. Almost every time when I restart or Shutdown my machine the drive is not being ejected properly and is in error state on next start.

Also, if I want to eject the drive manually, the OS won't allow that for there are apps that are still using the drive.

And it seems to be caused by Spotlight services, I can see the msd process if I run the command sudo lsof +d <the drive name>

I think there are issues with exFat handling in Sonoma.

I have a very similar issue with external my 12TB exFAT had disk. I have backed up my work on this external drive. Turns out Sonoma does not really support exFAT. It takes hours to mount on restart, will not index properly with Spotlight and I am having trouble removing it from Spotlight via privacy settings. It is also give me problems manually unmounting. This is basically a no win situation. I suspect the only work around is to format a separate drive with a mac friendly format and copy the files over. This is going to be incredibly annoying when I need to access the files with a PC.

Christian Bannister wrote:

I have a very similar issue with external my 12TB exFAT had disk. It takes hours to mount on restart, will not index properly with Spotlight and I am having trouble removing it from Spotlight via privacy settings. It is also give me problems manually unmounting.

What is the exact make & model of this external drive?

How is it connected to the Mac? Have you tried a direct connection to the Mac? And tried disconnecting all other external devices in case one of them is causing a problem to affect this drive? Tried using another USB-C port?

Try booting into Safe Mode to see if it makes any difference.

Experiencing the same thing (v14.4.1)

External SSDs are fine, but not my Western Digital (14TB and 8TB) are extremely slow and I have to resort to running First Aid (no issues found) just to get them to mount again. Even then it takes 20-30+ minutes.

Sometimes the issue can be due to a compatibility issue with one of the devices or a driver for one of those third party devices. A couple years ago I saw something similar reported by users on this forum with external hard drives and Wacom tablets when the Apple Silicon M1 Macs were first released...I don't recall if it was the M1 Macs or just macOS.

If you can narrow the issue down to one device being the source of the compatibility issue, then you can contact the manufacturer for assistance since they will have better luck fixing the problem and/or getting the attention of Apple to help them fix the issue or have Apple fix the issue themselves. Make sure all third party software is completely up to date and completely compatible with macOS Sonoma. Make sure you also have Sonoma completely patched as well.

You can open an official support ticket with Apple making sure to get an actual Apple engineer involved. At least then Apple will be aware of a problem. Unless users do this, Apple may not even be aware of any issues.

At the very least you should provide Apple with product feedback:

Feedback - macOS - Apple

It can be difficult to tell whether the issue is with Apple & macOS or whether it is an issue with one or more of the external devices or their third party drivers. It doesn't help that Sonoma seems to have a lot of bugs & compatibility issues and Apple is not forth coming with information.

I'm still having this issue with my SanDisk Professional G-DRIVE 5 TB. Splitting it up in two partition solved it first, but since 14.5 my MacBook Air M2 connected to the Studio Display (and the Drive connected there) has more issues than before. The machine hangs during boot if the drive is connected and it restarts after 2-3 minutes - only disconnecting the drive, booting the MacBook and then connecting the drive makes the disk appear after some time. I really hope Apple will fix those issues.

Some have reported issues with ExFat drives. I noticed that my write speeds to a drive formatted this way is very slow as compared to my Mac with Monterey however they seem to mount at the same speed as before.

I have a Mac Book Air connected to a Caldigit TS4 dock and a LaCie 2TB drive from the dock for Time Machine backups and a Samsung screen. This configuration worked fine until Sonoma 14.1. Now if the dock is connected the Mac hangs in start up after entering the password. To start up all has to be disconnected, the Mac started and when it is running the dock is then connected and everything works. Disconnecting the LaCie from the dock makes no difference. Plugging and unplugging stuff is a pain..and why does the set up not work after the Sonoma "upgrade"??

There is a Caldigit Firmware update for the TS4 dock (Version 13.1) which has now been applied. The MacBook Air still hangs on startup after entering the password when the LeCie drive is connected to the dock. Without the hard drive connected the MacBook/Dock/screen combo starts with no additional delay using the usual Magic Keyboard/Mouse.

After start up the external drive connects (takes a while),shows in Finder doing its TimeMachine stuff.

You might try using cloud storage like Dropbox or Google or One Drive. The files will be copied automatically to your PC without the disk format hassle. But the speed of your internet connection might limit the speed of the transfer.

If you have a fast router and LAN you could set up a server to be accessed by both PCs and Macs.

The above are just suggestions for work arounds. They do not address the root cause of your problem.