November 8, 20196 yr Hi Unraid Community, I'm currently trying to build my first Unraid server and I've come to the point where I want to install Unraid. During the setup of the Boot USB I've stumbled upon some inconveniences: Firstly the USB creation tool doesn't detect the (formatted to FAT32) USB Stick: So of course I tried doing it manually which gave me a "MBR DENIED" error: After some research I didn't find anything that could help me nor at all... Could someone please help me out? Yours sincerly, Coolmeesje PS: there is nothing wrong with my USB-Stick since I was able to make it a bootable disk countless times before (for Kubuntu/Win10). Edited November 8, 20196 yr by Coolmeesje the pictures didnt work and a small spelling mistake
November 8, 20196 yr Community Expert Your screenshots aren't working. Now that you have been approved, you should be able to attach them directly to your NEXT post. In future, please always attach instead of linking to an external site.
November 8, 20196 yr Author Just now, trurl said: Your screenshots aren't working. Now that you have been approved, you should be able to attach them directly to your NEXT post. In future, please always attach instead of linking to an external site. Thx, and I will. (I've also changed in in the post)
November 8, 20196 yr Community Expert Have you tried with a USB 2 port? Not sure it matters when creating the flash on another computer, but I do know many people have problems with flash booting Unraid in a USB 3 port. Also, are you sure there is only one partition on the flash?
November 8, 20196 yr Author 23 minutes ago, trurl said: Have you tried with a USB 2 port? Not sure it matters when creating the flash on another computer, but I do know many people have problems with flash booting Unraid in a USB 3 port. Also, are you sure there is only one partition on the flash? It's a Usb 2.0 port and a usb 2.0 stick, and I'm sure it has just one partition Edited November 8, 20196 yr by Coolmeesje more in detial
November 8, 20196 yr Community Expert Have you tried running the USB creator tool or the Cmd.exe in Administrator mode. I believe this is required.
November 8, 20196 yr Author 28 minutes ago, itimpi said: Have you tried running the USB creator tool or the Cmd.exe in Administrator mode. I believe this is required. I did and it wasn't the solution sadly.
November 8, 20196 yr Author Just now, ijuarez said: USB stick might not have a GUID whats the brand of the stick? Idk what GUID is, but the brand of my stick is HEMA. (A local store's home brand from the Netherlands)
November 8, 20196 yr Community Expert 4 minutes ago, Coolmeesje said: Idk what GUID is, but the brand of my stick is HEMA. (A local store's home brand from the Netherlands) GUID is the globally unique identifier required to assign an Unraid license to the flash drive. Without it you won't be able to use it with Unraid. Not saying it doesn't have a GUID, we don't know. And I don't know if that is any reason it shouldn't be able to prepare it for booting. Might be simpler if you just try a more reputable flash drive.
November 8, 20196 yr Author 41 minutes ago, trurl said: GUID is the globally unique identifier required to assign an Unraid license to the flash drive. Without it you won't be able to use it with Unraid. Not saying it doesn't have a GUID, we don't know. And I don't know if that is any reason it shouldn't be able to prepare it for booting. Might be simpler if you just try a more reputable flash drive. It does have a GUID. (I don't know how senitive it is so I did 'blur' some numbers)
November 8, 20196 yr Author 1 minute ago, trurl said: How large is the flash? 32GB is maximum for FAT32. its 8gb
November 8, 20196 yr How about using something like Rufus to pre-format the drive w/ MBR? It helped me when I had a USB stick not recognized during MSI BIOS updates. https://rufus.ie/ PS - I have never had luck with Unraid's USB flash creator, and have always had to do the manual copy of data + makebootable in admin mode. Edited November 8, 20196 yr by danull the PS
November 8, 20196 yr Author 44 minutes ago, danull said: How about using something like Rufus to pre-format the drive w/ MBR? It helped me when I had a USB stick not recognized during MSI BIOS updates. https://rufus.ie/ PS - I have never had luck with Unraid's USB flash creator, and have always had to do the manual copy of data + makebootable in admin mode. Thx so much! Ive found a loophole where i made it MBR with a Kubuntu iso using Rufus (the .zip for unraid won't work in rufus apperently). I then deleted all contents that was extracted from the iso. Extracted the unraid zip to the usb drive. Ran the cmd commandline and no more MBR rubbish!
November 8, 20196 yr Just a theory: virtually all USB flash devices come preformatted with either FAT32 or ExFat. If the device has some other file system, or perhaps no file system or perhaps cleared out MBR then Windows probably doesn't recognize the device in such a manner that function used to populate the device list in our Flash Creator doesn't see it. btw 32GB limitation is only for windows being able to format it using FAT32, larger devices windows will format using ExFat. Our Flash Creator can format devices larger than 32GB with FAT32.
November 8, 20196 yr Community Expert 41 minutes ago, limetech said: btw 32GB limitation is only for windows being able to format it using FAT32, larger devices windows will format using ExFat. Our Flash Creator can format devices larger than 32GB with FAT32. I knew there were ways beyond the native windows to format >32GB FAT32 but didn't know the Flash Creator would do it.
July 15, 20241 yr Hello, I have the same problem to replace my usb drive. Formatted it with RUFUS and no luck. Tried the trick to load Kubuntu as an ISO image with RUFUS and then wiping it and replace it with my USB backup. Still same issue that windows cannot update the MBR when running the make bootable.bat. Can anyone help here?
July 11, 2025Jul 11 Hi, just to close this out.The issue was with my tablet. When I connected to my laptop and generate the USB key, all was good.
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