External Thunderbolt SSD slow to mount on boot on M1

Has this external drive ever worked properly on this particular Mac? If so, then what has recently changed just before this issue began?

How was the drive encrypted?

What file system is on the external drive?

Try running Disk Utility First Aid on the external drive after the drive has been unlocked and mounted. Within Disk Utility click "View" and select "Show All Devices" so the physical drives and hidden Containers appear on the left pane of Disk Utility. Run First Aid on the physical drive, then run First Aid on the hidden Container. Even if First Aid says everything is "Ok", click "Show Details" and scroll back through the report to see if any unfixed errors are listed. You can try running First Aid several times to see if the error is fixed, otherwise you will need to erase the drive and restore the data from a backup.

Disconnect all other external devices in case one of them is causing a problem. Some other external devices may affect how external drives behave...most notably a Wacom tablet (apparently everything is fine as long as the external drives are mounted before connecting a Wacom tablet), but there may be other devices which could interfere as well.

Connect the external drive directly to the Mac. If you are using an adapter for the external drive, then try using another adapter. Maybe try using another data cable for the drive and try connecting the drive to another port.

Try booting into Safe Mode to see if you have the same issue.

You can try checking the health of the external SSD by running DriveDx. You may need to install a special USB driver in order to access the heath information on the external drive. Even with the special driver, some USB chipsets used by external drives/adapters/docks/hubs won't allow the necessary communication to access a drive's health information. Post the complete text report here using the "Additional Text" icon which looks like a piece of paper.

What is the exact make & model of the external SSD? You specifically mentioned Thunderbolt 3.... so there is a lightning bolt icon next to the USB-C port of the external drive? Most external SSDs tend to only utilize the USB3 protocol even though they have a USB-C type port.

Also, not all devices are compatible with an M1/M2 Apple Silicon Mac....usually older devices.

Hans D. wrote:

https://www.owc.com/solutions/envoy-express

Since this is just an enclosure, it means you purchased the actual SSD separately. What is the exact make & model of the M.2 SSD used with this enclosure?

Booting into safe mode wouldn’t, IMHO, prove anything, as the drive mounts even regularly, albeit delayed.

This is about eliminating third party software issues which may be interfering with the normal operation of macOS.

I will try that then. Still think it won't prove much as a lot of stuff doesn't get loaded in single-user mode, so if the drive mounts instantly, I still don't know why.

If Safe Mode works to allow the drive to mount quickly, then you at least know that you have an issue with some third party software. If you run the third party app EtreCheck, it will give us details on the third party software installed which is loading during boot and login. From assisting users on these forums, we can recognize some of the most likely apps known to cause problems to guide you on the best options. It is all about gathering information to better understand the problem. Of course both One Drive and Drop Box have startup items which will be disabled in Safe Mode, but this is about seeing whether the external drive mounts more quickly to eliminate hardware issues.

You would be surprised by the number of "ah ha" moments we get by doing things like this and seeing the results. Troubleshooting can be a long slow painstaking process especially if you don't have other items to swap & test.

Hans D. wrote:

Hi HWTech,

The port is a Thunderbolt 4 port (Mac Mini M1) and the OWC Envoy enclosure is Thunderbolt 3.

Can you provide a link to the product on OWC's website so I can see which exact drive/enclosure it is since they sell several different, but very similar models? Unfortunately most OWC products don't allow access to the drive's health information, so DriveDx probably won't work to access the health information on the external drive.

Was this a pre-built external drive, or did you purchase an empty enclosure and install the SSD? If the latter, then you could remove the SSD and connect it using a USB to SATA Adapter to attempt to access the SSD's health information using DriveDx.

Do you have another Mac available to test the external SSD to see if it has the same issue?

Booting into safe mode wouldn’t, IMHO, prove anything, as the drive mounts even regularly, albeit delayed.

This is about eliminating third party software issues which may be interfering with the normal operation of macOS.

I’m thinking more along the lines of needing to change the point in the startup process where drives get mounted?

The only way would be to make sure this is the only external device connected when booting the Mac. I don't know if there is a way to delay One Drive or Drop Box from launching, other than to launch them manually instead of automatically. Maybe another more knowledgeable contributor will have an idea for this question.