Trying to choose a USB boot device to use with my new machine (USB 2.0, USB 3.2 available). Pretty hard to find 32GB devices; I seem to remember reading something that going larger than a 32GB USB device was an issue because of the file system?

Is this still a thing in 2025/UnRaid 7.x?

Is there any advantage of using a USB 3.x speed device over a USB 2.0 device, either boot or usage wise?

Thanks in advance.

USB 2.0 sticks tend to run cooler and last longer. I'm not too sure about any size limitations.

4 hours ago, Gragorg said:

USB 2.0 sticks tend to run cooler and last longer. I'm not too sure about any size limitations.

Yeah I saw this video from SpaceInvader One

...and it seems like it's really about the manufacturer/model rather than USB 2.0 or not.

But the problem is that testing didn't take into account modern drives and the fact you can't easily buy =< 32GB devices anymore.

I guess the real question is, is there anyone actually running a drive > 32GB successfully?

Edited December 2, 2025Dec 2 by negated
typo

Not sure where you are located but amazon has a fairly large selection of 16 GB sticks

there is no need for <32G anymore. The restriction went away some Windows Versions earlier already.

Now you can create an (ex)FAT Partition with more then 32Gb and modern PCs can boot from it (keep your BIOS recent!)

But one thing from the old video still is important:

• put the stick into an USB2.0 port even if it is a 3.x one! This will slow it down and cool it down too. It will last much longer in 24/7 operations

• Boot speed will be faster slightly in 3.0 port, but you will regret it if the stick wears out quite fast. Boot Time is not really important, after the boot UNRAID runs from RAM, with full speed.

Edited December 2, 2025Dec 2 by MAM59

1 hour ago, MAM59 said:

there is no need for <32G anymore. The restriction went away some Windows Versions earlier already.

Now you can create an (ex)FAT Partition with more then 32Gb and modern PCs can boot from it (keep your BIOS recent!)

But one thing from the old video still is important:

• put the stick into an USB2.0 port even if it is a 3.x one! This will slow it down and cool it down too. It will last much longer in 24/7 operations

• Boot speed will be faster slightly in 3.0 port, but you will regret it if the stick wears out quite fast. Boot Time is not really important, after the boot UNRAID runs from RAM, with full speed.

Yup! Makes sense. Thanks. Does the Unraid USB tool do exFat itself or do you basically have to make it manually when you have >32GB?

Yup! Makes sense. Thanks. Does the Unraid USB tool do exFat itself or do you basically have to make it manually when you have >32GB?

Works automatically, although UNRAID still shows it as "VFAT"

10 hours ago, negated said:

Does the Unraid USB tool do exFat itself or do you basically have to make it manually when you have >32GB?

It was always possible to go greater than 32GB but you used to have to use 3rd party tools to handle formatting such drives as Windows used to be limited to a max of 32GB for FAT32 formatting. Interestingly even now using a tool such as Rufus to handle the formatting solves boot issues for some people regardless of drive size.

Interestingly even now using a tool such as Rufus to handle the formatting solves boot issues for some people regardless of drive size.

Rufus does a "cheap trick".

It creates a very small FAT32 partition and puts a special EFI Bootloader on it.

The remaining space is formatted with NTFS. The EFI Loader just mounts this NTFS partition and issues a 2nd boot from the EFI folder on the NTFS partition.

The main reason for this is not to extend the FAT32 space, but to get rid of the 4Gb file size limit of FAT. The current windows versions (the .WIM files) are larger than 4Gb and Microsoft had to split them up into several files which makes the installation not really easier (the DVDs contain the large single files, if you create a stick, these are split up and cannot be edited afterwards anymore).

So with a RUFUS formatted stick you can just copy over the DVD medium 1 to 1 and run setup from it.

Of course, such a stick can also boot other OS's like UNRAID because the RUFUS Bootloader allows reading NTFS filesystems whereas BIOS/UEFI only need to support FAT.

The Unraid USB tool also supports larger devices. I believe it still uses FAT32 but with a larger block size, I know I once used to create a 1TB external device, and it works.

Does anyone know if there's still an issue with some USB memory manufacturers NOT having serial numbers (that Unraid requires) for some of their USB memory sticks? I think that was going on with...SanDisk...at one point?

Common belief is that this wasn't the manufacturers making USB sticks without a unique GUID, but other 3rd parties counterfeiting USB drives with cheap Chinese early manufacturing run memory chips and off the shelf memory controllers. No need to burn a unique serial number in something that you will deny you every made, if asked.

And yes, counterfeit USB sticks are still an issue. Buy from a reputable source. Even better if comes from an actual store vs buying one online.

2 hours ago, ConnerVT said:

Common belief is that this wasn't the manufacturers making USB sticks without a unique GUID, but other 3rd parties counterfeiting USB drives with cheap Chinese early manufacturing run memory chips and off the shelf memory controllers. No need to burn a unique serial number in something that you will deny you every made, if asked.

And yes, counterfeit USB sticks are still an issue. Buy from a reputable source. Even better if comes from an actual store vs buying one online.

Thanks, makes sense.