External HD refuses access


Jun 27, 2020
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I have a Seagate 4TB HD that I reformatted for NTFS. I previously used it on my Mac.
Windows recognises the HD, but when I try to open it I get the following message: F:\ is not accessible. Access is denied. That's it. Can't open it.
I've tried changing the permissions to read & write, but no luck.
I've reformatted the drive via Disk Management, which took hours, but it still won't let me open the drive.

When I reformatted it on my Mac as exFat, ,the Mac recognised the drive, Windows did too, but I still couldn't open it. :-(

Any idea what is going on here and how I can kick this drive into action?
Last edited:


Sep 26, 2017
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I use WDC 4TB drive that came with the mention of Windows and Macintosh on the packaging and formatted as exFAT. Since I no longer had my MacBook Pro I first used Disk Management to delete the partition on it then created a new partition then formatted as NTFS and assigned a drive letter to it.

Mac OS X and the newer macOS have limited support natively for NTFS-formatted drives, usually need additional software so exFAT would be better for interchangeability.

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