Level 1

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Bootcamp Win installed on external SSD - Win won't recognize MBP internal SSD formatted ExFat or NTFS

So, after repeated attempts to load Win on my internal MBP SSD via Bootcamp Assistant, and weeks of unsuccessful solutions from the Apple Service Center, (a "reinstall Win loop" which is plaguing more and more people), I opted for installing Win on an external SSD I had and connecting to my MBP via USB. (There is an excellent YouTube that guided me through this process effortlessly - "How to install Windows 10 "Boot Camp" on a Mac External Drive the EASY way! (2020 edition)""https://youtu.be/3IhW722IMwE")

However, now while my MBP sees the Win partition and files on the external SSD when I am operating under OS, the opposite is not true. When running Win from the external SSD, while it sees the internal SSDs partitions, it cannot "access" them, e.g., copy to, etc. , even though I have formatted one partition ExFat and one NTFS.

Note that while the NTFS partition is labeled "BOOTCAMP", it is empty.

Windows, Windows 10

Posted on Sep 17, 2020 4:03 AM

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24 replies

Loner T

Level 9

59,536 points

Sep 20, 2020 9:14 AM in response to Jbvoigt

Jbvoigt wrote:

No, I did not manually assign drive letters. They were automatically assigned. However, based upon your question, I did change drive letters on both via Window's Disk Management. The letters readily changed and stuck through a restart. An attempt to copy a file from C: to P: was as unsuccessful as before when the drive was F:. *sigh* I have since returned the drive letters to their original state.

Normally, drive letters should not be changed using Windows Disk Management, because it causes issues. In Windows CMD window with Administrative privileges, can you run diskpart and post the output of

list disk

list volume

Loner T

Level 9

59,536 points

Sep 17, 2020 1:53 PM in response to Jbvoigt

Can you boot into macOS and copy files from macOS to the exFAT partition?

From macOS Terminal, post the output of

diskutil list

with the external disk connected.

Loner T

Level 9

59,536 points

Sep 18, 2020 1:28 PM in response to Jbvoigt

Now connect the external Windows disk, boot from it, and try to copy the .jpg from the exFat to the external SSD.

Jbvoigt Author

Level 1

13 points

Sep 18, 2020 9:24 PM in response to Loner T

File copied to ExFat partition on internal drive. And it opens.

Jbvoigt Author

Level 1

13 points

Sep 18, 2020 9:26 PM in response to Jbvoigt

Booted into Windows, the ExFat partition of the internal drive shows up, but files in it won't open.

Loner T

Level 9

59,536 points

Sep 19, 2020 7:56 AM in response to Jbvoigt

Can you copy the file from F: to C: and try to open it? Do you have any third-party NTFS software installed?

Loner T

Level 9

59,536 points

Sep 20, 2020 11:36 AM in response to Jbvoigt

Using the https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/diskpart as reference, can you check the attributes of each volume - 0, 1 and 3? Are any of these read-only?

Jbvoigt Author

Level 1

13 points

Sep 21, 2020 2:33 AM in response to Loner T

No, none seem to be "read-only".

Loner T

Level 9

59,536 points

Sep 21, 2020 6:18 PM in response to Jbvoigt

Can you Identify your MacBook Pro model - Apple Support exactly? Also, see the post on Stuck in a loop for boot camp download - Apple Community.

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Bootcamp Win installed on external SSD - Win won't recognize MBP internal SSD formatted ExFat or NTFS