Forum Discussion
Windows on exFAT has some bugs
As shown in the screenshot attachment, when using the exFAT file system as the system volume to run the latest version of Windows 11 Build 27686, the following bugs exist:
Windows 11 on exFAT.jpg
1. When the Shim DataBase file exists, the system UWP such as the start menu and settings cannot be opened. If you delete the file named "RandomGUID.sysmain.sdb" in the "C:\Windows\apppatch\MergeSdbFilesSource" directory, or delete the registry "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\SdbUpdates" item, the problem can be solved. This bug has existed since Win11 v22H2 two years ago and has not been fixed yet.
1 Shim DataBase bug.gif
2. When the Smart App Control function is in the evaluation or enabled state, the operating system will run very slowly. If you set it to off in app & browser control in Windows Security, or directly change the "VerifiedAndReputablePolicyState" key value in the registry "HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CI\Policy" to "0" to turn it off, the problem can be solved. This bug has existed since Win11 v22H2 two years ago and has not been fixed yet.
2 Smart App Control bug.gif
3. Check Disk Utility will throw an error when checking exFAT volumes with a total number of clusters between 2^30 and 2^32 (that is, the FAT table size is between 4GB and 16GB), but in fact the volume is completely normal and not damaged. In addition, according to the exFAT file system specification, a single exFAT volume can have a maximum of 4294967295 allocation units, which means that the maximum partition capacity supported by formatting with 4KB clusters is 4096Byte×2^32Byte=16TB. However, when trying to load a volume of this size, it takes a long time to complete the operation, which may be another bug.
3 Chkdsk bug.gif
4. The change partition size function in the disks & volumes in the new system storage settings will cause file system corruption and loss of all data when operating on exFAT volumes. If the volume is a system partition, it will immediately trigger BSOD and cause the OS to completely crash and fail to start. This is a very dangerous bug.
4 Change data partition size bug.gif4 Change system partition size bug.gif
5. When the system Blue Screen of Death occurs, the DUMP file cannot be generated normally in the exFAT volume. This seems to be a bug in exfat.sys.
5 BSOD dump bug.gif
6. When the system volume is exFAT, the hiberfil.sys file cannot be created normally, resulting in the inability to use the hybrid boot function. The 0xc0000010 error will also be prompted through command line operations. This seems to be a bug in exfat.sys.
6 Hibernate file bug.gif
7. Every time try to run a user UWP app such as Microsoft Store, the AppX Deployment Service will repeatedly stop abnormally, causing the UWP program to crash immediately. This seems to be a bug in AppXDeploymentServer.dll.
7 AppXSVC crash bug.gif
Please fix these bugs, thanks!
In addition, it usually takes a long time to boot Windows in the exFAT volume. Can you optimize the boot speed of exFAT system volumes in OS Loader?
Note:
exFAT install Build 27686.jpg
If you want to use exFAT or ReFS as the Windows system volume, you need to use NTFS to complete the system installation first, then restart and enter Windows PE to open CMD.exe and execute the following command to capture the .WIM image file:
Dism /Capture-Image /ImageFile:D:\Backup.wim /CaptureDir:C:\ /Name:Backup
After capturing the .WIM image, execute the following command to format the system volume C:\ to the exFAT file system:
Format C: /FS:exFAT /Q /A:4096 /Y
After formatting, execute the following command to apply the .WIM image file:
Dism /Apply-Image /ImageFile:D:\Backup.wim /Index:1 /ApplyDir:C:\
After the .WIM image is applied, restart and finally the system will boot from the exFAT volume.
exFAT boot Build 27686.jpg- After testing, Build 27695 has not fixed these bugs.
- Microsoft doesn't support installing and booting Windows from exFAT volume. Please note that NTFS volume is supported for installing windows and booting from it. exFAT doesn't contain certain features needed to support installing and booting Windows. So we encourage to use NTFS as boot volume and if you experience other issues you mentioned then we can help.
PaddyA320
In fact, Microsoft has added the bootable exFAT feature as early as 2010, and the first system version that supported exFAT boot was Windows 8 Milestone 1 Build 7779.
6.1.7779 exFAT boot.jpg
This is a hidden feature that few people know about, just like there are many undocumented APIs inside Windows, but Microsoft has not officially announced the implementation of such features.
Similarly, the bootable ReFS feature was added as early as 2020, and the first system version that supported ReFS boot was Windows 10 Iron Dev Build 20185.
10.0.20185 ReFS boot.jpg
In addition, I am also the first person to research exFAT and ReFS boot Windows and publish installation tutorials. You don't have to question that these are facts.
- ExFAT has limitations when it comes to being used as a system volume. For example, it doesn't support journaling, which can lead to file system corruption issues.
Audret
It's not a big problem. If there is an error in the file system, you can use the chkdsk.exe utility to scan and repair it.
My main computers has been using exFAT to deploy Windows 10 and has been running in a production environment for 5 years. It has been working stably and has never been damaged since daily use.- I've read that ExFAT has some limitations when used as a system volume, particularly the lack of journaling, which can increase the risk of file system corruption. Have you experienced any issues with ExFAT in critical use cases, like as a system drive or for larger data handling? How do you usually work around its limitations?
- Build 27723 has not fixed these bugs.
- While exFAT is designed for larger files and storage devices, some users have noted that performance can lag, especially with high I/O operations compared to NTFS.
