# My Book Studio for Mac - Showing 3TB with a 4TB HDD after Upgrade

**URL:** <https://forums.sandisk.com/t/my-book-studio-for-mac-showing-3tb-with-a-4tb-hdd-after-upgrade/413473>\
**Category:** External SSD for macOS\
**Created:** [September 29, 2024, 11:25pm UTC](https://forums.sandisk.com/t/my-book-studio-for-mac-showing-3tb-with-a-4tb-hdd-after-upgrade/413473 "2024-09-29T23:25:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![RafaChaves](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@RafaChaves](https://forums.sandisk.com/u/RafaChaves)\
**Post date:** [September 29, 2024, 11:25pm UTC](https://forums.sandisk.com/t/my-book-studio-for-mac-showing-3tb-with-a-4tb-hdd-after-upgrade/413473/1 "2024-09-29T23:25:01Z")

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Hello WD Community,

In 2013, I purchased a My Book Studio for Mac external hard drive with a 3TB capacity. The unit served me well until recently, when it began making a loud noise and eventually failed. Initially, I thought the noise was from the cooler, but it turned out to be the disk itself, since it has no cooler whatsoever inside it.

I really like the enclosure—it’s a beautiful silver metal—so I decided to replace only the internal hard drive rather than the entire unit. Upon disassembly, I found that the original drive was a 3TB green model, which is no longer available. Instead, I purchased a brand new 4TB blue drive, the proper sucessor in my understanding.

I successfully installed the new drive inside the enclosure, but my Mac still reads the device as a 3TB unit. While WD Drive Utilities app recognizes the full 4TB, Finder only displays it as 3TB.

Could this be a limitation of the enclosure’s circuit board? I chose the 4TB model because it is compatible with the My Book Studio, as confirmed on Amazon: [link](https://www.amazon.com/Book-Studio-External-Drive-Storage/dp/B0090A8TYA).

If anyone has insights on how to resolve this and access the full capacity, finding this missing TERABYTE, I would greatly appreciate your help!

Thank you so much!

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**Author:** ![kumburle.pradeep](https://avatars.discourse-cdn.com/v4/letter/k/c5a1d2/32.png) [@kumburle.pradeep](https://forums.sandisk.com/u/kumburle.pradeep)\
**Post date:** [October 1, 2024, 12:02pm UTC](https://forums.sandisk.com/t/my-book-studio-for-mac-showing-3tb-with-a-4tb-hdd-after-upgrade/413473/2 "2024-10-01T12:02:49Z")

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Hi @RafaChaves

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting:

> **[Western Digital Support | Western Digital](https://support-en.wd.com/app/askweb)**
>
> Not finding the answer to your Western Digital storage product question? You can ask your Western Digital Support question here.