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Why Does Toshiba External Storage Partition Grey Out On Mac?

I am trying to partition my new Toshiba external drive, which I have just reformatted to "Mac OS Extended (Journaled)," by clicking erase, and it said "done." I looked at another thread https://https://discussions.apple.com/thread/8132985 that answer did not solve my problem since the case is slightly different (I don't have a subfolder to click on). I cannot proceed to the next step bc the partition button is greyed out. Would appreciate some answers and a speedy response, thanks so much!

Best Answered by

iBoysoft author Vain Rowe

Vain Rowe

Answered on Tuesday, August 5, 2025

Hi there, based on your description, I suggest you click the View button and then select the View All Drives option to check if the new partition you created shows up in Disk Utility.

If not, create a partition again and decide it GUID Partition Map in Scheme since MBR Partition Map only works fine on Windows devices but not macOS computers.

Take care~

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