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Sharing & Permissions on SSDs: "You have custom access"

I have recently bought two SSDs for my MacBook Pro 16", with USB-C connections (drives are two different brands, Samsung and WD), running OS 10.15.5.


In both cases, Time Machine insists on excluding them (the two drives are greyed out and can't be removed from exclusions).


When I "get info", both drives have "You have custom access" under Sharing and Permissions, and there seems to be no way to change that. I suspect that is the reason?


Disk Utility comes up with an error when I try to reformat them. I can change the names of the drives though.


Any idea what this problem is?


MacBook Pro 15″, macOS 10.14

Posted on Jun 5, 2020 6:46 AM

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Posted on Jun 5, 2020 6:29 PM

You may need to first erase the drive using Disk Utility before the drive can be used with macOS. I've seen reports that if Windows 10 formats a drive with ExFAT that it may use a larger block size for the file system which macOS doesn't recognize.


Make sure to backup any data from the drive before erasing the drive.

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Jun 5, 2020 6:29 PM in response to simon0672

You may need to first erase the drive using Disk Utility before the drive can be used with macOS. I've seen reports that if Windows 10 formats a drive with ExFAT that it may use a larger block size for the file system which macOS doesn't recognize.


Make sure to backup any data from the drive before erasing the drive.

Jun 5, 2020 9:46 AM in response to simon0672

maybe....simon0672. plug them into your MacBook Pro 16" , both should work, for now. click on them after they appear on your Desktop, and do a get info on them (*command/Apple+I) and down at the bottom of the info window that comes up for each drive you should see sharing and permissions, and a padlock. Believe it or not, the default for Catalina is to make all drives read-only, not read and write. You can change this. click the padlock at the bottom of the window to unlock it. You'll need your user/login name and password which you'll be asked for, and then click on the user on one column, and see what that's set to. If it's read, set it to read and write, same goes for system. Apparently Catalina does stuff a little differently and introduces System Integrity Protection (SIP)



I hope you're not as confused as I am


jb

Jun 5, 2020 5:10 PM in response to simon0672

simon0672 Said:

"[...]When I 'get info', both drives have 'You have custom access' under Sharing and Permissions, and there seems to be no way to change that. I suspect that is the reason?[...]"

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Firewall Settings:

Do you have Security Software installed? If so, uninstall it (get the uninstaller from the manufacture and nowhere else. Elsewise, it could end up being Malware or Spyware you install). It has firewall settings which disallow connected devices. Security Software gets in the way on a Mac, and this is a put example of how.

Jun 5, 2020 7:39 PM in response to HWTech

Thank you very much.


Yes that has now worked. I had tried re-formatting last night but Disk Utility kept deciding it was not possible (even after several restarts of the computer).


It seems that having rested overnight, Disk Utility has decided to reformat the drive!


Thanks for taking the time to reply, it is appreciated.


Sharing & Permissions on SSDs: "You have custom access"

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