“I have formatted my external hard drive with exFAT file system on my Mac machine running with OS X 10.7. Later I upgraded to OS X 10.8. Whenever I plugged the ExFAT drive to my Mac system, an error pops-up saying that “iMac doesn't recognize this drive”. I tried to fix this issue through permissions in Disk Utility, but no use. Few of my vital files are present on the ExFAT drive along with music, movies and photos. I am at loss; I have no clue, what else should I do to access my drive. I am looking for help. Please guide me.”
It’s damn difficult to bear the brunt of losing your irreplaceable data all of a sudden. But you should never lose hope at any point of time. According to the great saying, you can find solution for every problem in the world! Then why not for unrecognized ExFAT drive? Have a look here.
Why Mac cannot recognize the ExFAT drive?
There might be two causes here.
1) Mac might be missing some necessary driver software to read the ExFAT drive, after you upgraded from previous OS X
Using your Samsung T5 for Time Machine means you have to change the as sold formatting from ExFAT to Mac OS Extended (Journaled). Follow the steps 1 to 6 above and you’ll do that. Then you can read this how to use article to connect your Samsung T5 to Time Machine. Use the link to the article and use the Table of Contents to drop down to the. Mar 07, 2016 It is not open source. ExFAT is the file system I recommend for external USB disks. Fortunately for Mac users, Apple has an agreement with Microsoft and so OS X supports exFAT drives (as of Snow Leopard). You can plug in an external exFAT USB drive and read and write to it on your Mac.
ExFAT has been around for awhile, but we've never really talked about it. Essentially, it's a file system that's both readable and writable on any modern Mac or Windows machine (sorry, Leopard users).
2) There might be some issue with your ExFAT drive
How to go with further troubleshooting?
1. Check Apple website for availability of any update/driver software for current version of your OS X. If you find any, install them on your machine and try to access the ExFAT drive. If you are unable to open the ExFAT drive even after installing adequate update and driver program, then jump to next method.
2. Plug-in the ExFAT drive into another working Mac Machine and see it is detected. If the drive is recognized, copy your entire data from it. Detach the drive and format it on your host Macintosh (on which your drive was not detected).
In case, your drive fails to show up on any other Mac machines then it seems like the problem lies within the ExFAT drive. It might be corrupted or became unreadable. Still don’t worry. You can bring back the corrupted ExFAT drive to normal state (working mode) by formatting/re-formatting it. Also you need to be concerned about data saved on the unrecognized ExFAT drive. As you can safeguard entire data present on your undetected ExFAT drive, with the help of Yodot Mac Data Recovery application.
Tool to recover undetected ExFAT drive on Mac system:
Yodot Mac Data Recovery can easily backup whole data from your undetected ExFAT drive, without causing any intact either to drive’s internal structure or to files stored on it. The program is well fitted to restore unrecognized Samsung hard drive, Toshiba external disk, Seagate portable drive, ScanDisk media card, HP Pen drive, Kingston USB etc i.e. it supports variety of storage devices as well as various brands; so you can undoubtedly trust the software to achieve guaranteed data restoration on any storage media. The retrieving ability of this utility is unbounded, thus you can recover any files like Office document, Portable Document Format (PDF), Outlook data files, archives, audio, video, images, RAW pictures etc of more than 300 types. Not just from corrupted storage, even inaccessible, dead, crashed, non-booting and un-mountable Mac machines data can also be retrieved by this software, with no difficulty. The smart interface of the program offers you a great data retrieval experience, effortless recovery process and preview of recovered data, so that you can review its recovering capability before you save regained data. The companionable toolkit is well-suited for all latest editions of OS X from Leopard to Sierra.
Steps to restore undetected ExFAT drive on Mac:
- Get Mac Data Recovery on your Macintosh system
- Attach undetected ExFAT drive
- Go for Volumes Recovery selection on main screen
- Select ExFAT drive and its all shown volumes from list
- Choose Normal Scan and click on Mark All key
- All files present on your ExFAT drive will be listed in two views
- Mark files that you need
- Save those files on Macintosh hard drive
Note:
- It’s suggested to keep an untouched backup of entire data prior to start OS upgrade
- Don’t forget to install necessary updates as well driver software after upgrading your OS
Summary :
Which allocation unit size should you use for an exFAT partition? What is the best allocation unit size for exFAT format? If you are confused about the allocation unit size exFAT, don't worry. This post from MiniTool will show you how to set the right allocation unit size for exFAT partition.
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When you try to create or format a drive to exFAT with disk management tools, you are able to choose a proper allocation unit size for the exFAT partition according to your needs. However, not many users have a clear understanding about what allocation unit size is and what allocation unit size they should use for exFAT format.
Here is the full guide of NTFS vs FAT32 vs exFAT. Check out this post to know the differences.
Given that, this post will demonstrate you what allocation unit size is and how to set the best allocation unit size for exFAT format. If you are interested in this, please keep on reading.
About Allocation Unit Size
In computer file systems, a cluster or allocation unit refers to the smallest logical amount of disk space that can be allocated to hold a file. We know that hard drives are divided into many clusters to save data on it, but how big is a cluster? Well, the size of a single cluster is decided by the allocation unit size selected when the partition is created or formatted.
Macos Mount Exfat
So, allocation unit size is also known as cluster size, which determines the smallest chunk of disk space that holds a file.
What is allocation unit size? What is another name for a file allocation unit? How can you change allocation unit size? You will get the answers in this post.
When you create or format a partition, you can set the allocation unit size for the partition. And usually, the allocation unit size will be set as Default, as many people don't know what it is and how to set it. So they just use the default value for the allocation unit size. And some users don't even notice the allocation unit size option.
Actually, the allocation unit size or cluster size can influence your disk performance or disk space utilization. If the allocation unit size is not set properly, it may reduce the data read-write speed and waste a lot of disk space.
So it is very necessary to change cluster size reasonably. And before changing cluster size for your partition, you can check out the following contents to learn what the best allocation unit size is or what allocation unit size should you use for exFAT.
What Allocation Unit Size Should I Use for exFAT?
As mentioned before, cluster size represents the smallest amount of disk space that can be used to hold a file.
One cluster can only hold one file, but one file may take up multiple clusters depending on the file size and the cluster size. This is to say, if the file's actual size is smaller than the size of a cluster, it will still take up a cluster. If the file's actual size is more than a cluster, the file will take up two or more clusters.
Therefore, if you save large files to a drive that uses small clusters, data read-write speed will be reduced, because each file is broken into small pieces and it needs time to gather all the broken pieces and access them as one. If you save small files to file system with large clusters, a lot of disk space will be wasted. And that’s why you should set cluster size reasonably.
So we get this conclusion: if the size of the files you want to store on the drive is large, then a large cluster size is recommended, which will increase the data read-write speed. If you plan to store lots of small files, it is advisable to set a small cluster size, which can improve the disk space utilization.
If you have no idea about your file size and unit, Default is also a good choice. It will choose a proper cluster size for your drive based on the capacity. For example, according to Microsoft, the executing standard of default cluster size for exFAT is:
- 7MB – 256MB: 4KB
- 256MB – 32GB: 32KB
- 32GB – 256TB: 128KB
- >256TB: Not supported
Which allocation unit size you should use for exFAT format? Now you should know that it depends on the size of the file you will store on the exFAT drive. Besides, if you want to learn more information about the default cluster sizes for other file systems, you can check out this post from Microsoft: Default cluster size for NTFS, FAT, and exFAT.
How to Change Allocation Unit Size for exFAT
Now you should it is necessary to choose a proper allocation unit size for your exFAT, NTFS to FAT32 partition. If you want to change cluster size to improve your disk performance or enhance the disk space utilization, you can try the following two methods to change allocation unit size for exFAT partition.
Change Allocation Unit Size exFATwith MiniTool Partition Wizard
MiniTool Partition Wizard Free Edition is an all-in-one partition manager, which can help you manage NTFS, FAT32 and exFAT partitions in a simple way.
As a powerful partition manager for Windows users, it can help to move/resize partition, format partition, extend partition, copy disk/partition, convert NTFS to FAT32, convert MBR to GPT and check file system and so on.
With the Format Partition feature in MiniTool Partition Wizard Free Edition, you can clear all the partition data and then reconfigure parameters such as partition label, file system and cluster size for the specified partition. So, by formatting the drive, you can reset the allocation unit size exFAT so as to meet your actual demands.
Here are detailed steps:
Step 1.Download MiniTool Partition Wizard Free Edition by clicking the following button. Then install and launch MiniTool Partition Wizard to get its main interface.
Step 2.Then select the partition which needs to reset cluster size and choose Format Partition feature from the left panel.
Step 3.On the pop-up window, you can set partition label, file system and cluster size for the selected partition. Set the file system to exFAT and choose a cluster size from the drop-down menu according to your needs and then click OK.
Step 4.Preview the changes you just made. At last, click the Apply button to allow the change.
Change Allocation Unit Size exFATwith Command Prompt
Command Prompt, is also known as CMD, is the command-line interpreter available in Windows operating system. It can help you perform a lot of operations to solve various Windows problem and manage disks and partitions.
If you are familiar with Windows 10 Command Prompt, You can also use Command Prompt to format your partition and change its allocation unit size with commands. Just follow the steps below.
Step 1: Type cmd in the Windows 10 Cortana search box and right click the best match Command Prompt to select Run as administrator.
Step 2: In the Command Prompt window, type diskpart and hit Enter.
Exfat For Mac Os X
Step 3: then type the following commands one by one and hit Enter after each:
- List disk
- Select disk * (* refers to the number of the target disk or partition)
- List partition
- Select partition *
- Format fs=exFAT unit=32k (you can just change the 32k to other allocation unit sizes you want.)
After the above commands are executed successfully, you can store files to the exFAT partition with the new allocation unit size.
You may be interested in this post: 10 Command Prompt Tricks that Every Windows User Should Know
Bottom Line
After reading this post, now you should know what allocation unit size you should use for exFAT partition and how to change exFAT allocation unit size or cluster size with two different methods.
If you have any good idea on allocation unit size for exFAT format or if you have any question about how to change cluster size exFAT with MiniTool Partition Wizard Free Edition, you can leave a message on the following comment zone and we will reply as soon as possible. If you need any help when using MiniTool software, you can contact us via [email protected].
Allocation Unit Size exFAT FAQ