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Announced on October 16, 2014, identifiable by the model number A1347 and EMC 2840.

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usb 2 external ssd slow to boot

hello I have a samsung T7 ssd connected to my Mac via usb 3, it seems very slow and the system takes a long Time to boot up, and open applications, I have run black magic disk speed test and get these results 37.1MB/s write and 34.7mb/s read, I have also tried connecting the drive with the usb-c cable using a usb-C to usb A adaptor which I get speeds of 400mb/s read and 380mb/s write but I have found this connection frustrating because I Have the machine set to shut down on a Friday and boot on a Monday ,and when the drive is connected via the usb-c to usb-a adaptor and tries to to boot on Monday on the screen I get a file with a flashing question mark and I have to restart with the power button and it boots and runs until the Friday shut down , any ideas why the drive would be running slow or not able to be found when set to boot up on a certain day.

thanks in advance


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The flashing ? Is because the systems firmware is not finding what it thinks is the boot drive. Basically you’ve got it set for a different drive that what you want, go into the Startup preference setting and with the drive connected alter it to use that drive.

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I have tried what you said, when I go to system preferences and select startup disk there is only one drive there and that is my ssd boot drive , when I try and schedule a restart the system just boots to the flashing question mark and I have to press the power button to get it to boot normally this could happen up to three times before the system boots, could the problem be the Usb-c to usb converter that I am using with the usb-c cable


@lethal99887 - Sorry it’s likely a timing issue between the interface conversions. What happens when you use a USB-A thumb drive or Thunderbolt connected bootable drive?


when I boot with the same drive using a usb-A cable it's boots fine, I have just swapped the usb-c cable and so far there doesn't seem to be an issue


@lethal99887 - I think that nails it. I have a bunch of the T5 drives but I used them for data only. I don’t think Samsung expected people to use the drives as boot drives.


thank you for your help


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