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Frequently Asked Questions

If you need help with Unraid OS, you have several support options:

Index​

Build & Hardware​

I need help with a build or system configuration. Where do I go?
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For guidance on building or upgrading your Unraid server, visit the Compulsive Design forum or join the Unraid Discord. The community is active and ready to assist you, no matter your level of experience.


What controllers are recommended for Unraid?
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Unraid performs best with non-RAID Host Bus Adapters (HBAs). It's best to avoid hardware RAID controllers, which can obscure drive health information and complicate maintenance.

Always check for firmware updates and ensure the controller is set to HBA/IT mode, not RAID mode. You can refer to the Recommended Controllers thread for models that the community has tested successfully.


What's the best way to add more storage if my built-in controller is full?
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Unraid allows for the expansion of storage across multiple controllers. You can add a compatible HBA (as mentioned above). Ensure the controller operates in standard HBA (non-RAID) mode and supports AHCI/SATA. Avoid using RAID-only cards, as Unraid requires direct disk access for parity and monitoring.


Does Unraid have an allocation feature that remembers bad sectors on drives to prevent writes to them?
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Unraid utilizes SMART data from your drives to monitor their health and detect issues such as bad sectors. SMART is built into modern hard drives and SSDs, tracking attributes such as reallocated and pending sectors.

While Unraid doesn't have a specific allocation feature to avoid bad sectors, it does use SMART data to notify you if a drive displays signs of failure or has an increasing number of bad sectors. This information can be found in the WebGUI under the drive's health status and SMART attributes.

If a drive shows a high count of reallocated or pending sectors, consider replacing it soon to prevent data loss.

If you're uncertain about a drive's health, you can share your SMART data in the General Support forum for assistance from the community.


OS & Configuration​

Can I use a HASP key within a VM on Unraid? How does that work with multiple VMs?
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If your HASP key is a USB dongle, you can assign it to only one VM at a time. Note that two VMs cannot use the same key simultaneously. You might need to pass through an entire USB controller for better compatibility. Always run tests with a Trial license to confirm that your hardware performs as expected.


My USB flash has failed, and I don't have a backup. How do I restore my configuration?
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If you had Unraid Connect enabled for Flash Backups, you can use it to restore. If not, get a new, high-quality flash drive, install Unraid on it, and use the registration key you received via email. Reassign your drives as they were. If you can't recall the assignments, post for assistance in the General Support forum.


What should I do if I have forgotten my root password?
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Refer to Reset your password.

note

If you’re using encrypted drives and forget the encryption password, data recovery isn't possible - there is no backdoor.


How do I completely start Unraid OS from scratch? (Factory reset procedure)
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  1. Backup any data you wish to keep.
  2. Stop the array and shut down your server.
  3. Remove the USB flash device.
  4. Use the Unraid USB Flash Creator tool to reformat and reinstall Unraid onto the flash drive.
  5. Reinsert the flash device and boot your server.
  6. In the WebGUI, open a terminal and run lsblk to list all drives (excluding the flash).
  7. Wipe existing filesystems from each data drive:
Critical: Destructive Operation

This step will permanently erase ALL data on the specified drive(s) and is IRREVERSIBLE!

  • Verify you have backups of any data you need before proceeding

  • Double-check the device identifier in the WebGUI or with lsblk before running this command

  • Ensure you're targeting the correct drive - data loss from the wrong drive cannot be recovered

For each data drive, run:

wipefs /dev/sdX

Replace X with the correct drive letter (e.g., sda, sdb, sdc)

  1. Continue with the normal Unraid setup and configuration.

How do I change the hostname of my server?
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To change your Unraid server's hostname, navigate the WebGUI to Settings → System Settings → Identification.

Effects of changing your hostname:

  • The new hostname will be used for network identification (e.g., access via http://newname).
  • You might need to reconnect any mapped network drives or shortcuts using the new hostname.
  • Some devices or services may cache the old name; a full device reboot may be required to recognize the new name.

My flash drive is reporting an invalid GUID. What do I do?
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Unraid requires a USB flash device with a unique hardware GUID (serial number). Some manufacturers may reuse GUIDs or use generic values, making these drives incompatible with each other.

Field-tested brands:

  • Samsung FIT Plus / Bar Plus
  • Kingston DataTraveler Exodia
  • Lexar JumpDrive M45
  • PNY Elite-X (Avoid newer SanDisk Ultra Fit/Cruzer models unless you can confirm a unique GUID.)

It's best to avoid generic or unbranded drives, SSDs, USB card readers, and SD card adapters, as these often lack unique GUIDs and may not be supported for booting Unraid.


Virtualization & Devices​

Whenever I shut down my Windows VM with an AMD GPU assigned, it fails to restart. What can I do?
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Many AMD GPUs experience issues with function-level resets, which contribute to this problem. Workarounds include ejecting the GPU from within Windows before shutting down or using an NVIDIA GPU, which generally avoids this issue.


How do I pass through my primary GPU to a VM if my CPU has no integrated graphics?
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This is feasible but requires additional steps. Check out SpaceInvaderOne’s video guide for detailed instructions on how to do this properly.


Storage & RAID​

Does Unraid support various RAID types such as RAID1/5/6/10?
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Unraid features a unique storage architecture that distinguishes it from traditional RAID systems. Here's a comparison of different storage options:

Feature / CapabilityUnraid parity array (md)BTRFS pool (cache)ZFS pool (7.x+)Traditional RAID 1/RAID 5/RAID 6/RAID 10
Parity / redundancy modelDedicated parity disk(s)Software RAID 1/RAID 10/RAID 5/RAID 6 via BTRFSRAID 1-Z1/Z2/Z3 or mirrorsStriped parity (RAID 5/RAID 6) or mirrors (RAID 10)
Data stripingNoYes (except RAID 1)YesYes
Disk size flexibilityMix any sizesBest when similar sizesBest when similar per vdevRequires matched sizes
Expand one disk at a timeYesYes (add or replace devices)Yes (per vdev*)Typically no
File system per diskYesNoNoNo
Single-disk read speedNative disk speedAggregate (multi-disk)Aggregate (multi-disk)Aggregate
Write degradation during rebuildMinimal (only failed drive)Depends on levelDepends on vdev layoutSignificant
Bit rot detectionOptional (BTRFS/ZFS checksum)✅ Built-in✅ End-to-end checksums❌ Not inherent
Snapshot / send-receive❌✅ (BTRFS)✅ Native❌
Recommended production useGeneral media storageRAID 1/RAID 10 (avoid RAID 5/RAID 6)**✅ All levels stableEnterprise arrays

* ZFS vdevs must be expanded by replacing all drives in the vdev or adding a new vdev.
* BTRFS RAID 5/RAID 6 remains flagged as "experimental" upstream; use with caution.

  • Unraid parity array is excellent for incremental expansion, allowing mismatched drive sizes with minimal rebuild stress.
  • ZFS pools (available in 7.x) provide enterprise-class redundancy, snapshots, and checksums, making them ideal for VMs and databases.
  • BTRFS pools excel for fast SSD caches, especially in mirrored RAID 1/RAID 10 mode.
  • Traditional hardware RAID cards are not necessary; you can use simple HBAs to allow Unraid to manage drives directly.

I currently have an array of devices formatted with an MBR-style partition table and want to convert to GPT. How do I do that?
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Why convert from MBR to GPT?

MBR (Master Boot Record) partitioning supports disks up to 2TB and only allows a maximum of four primary partitions. On the other hand, GPT (GUID Partition Table) can handle much larger disks and nearly unlimited partitions. Converting to GPT is advisable if you work with larger drives or want better partition management.

Use Maintenance Mode

Before starting the conversion process, put your array into Maintenance Mode. This step ensures no writes occur during the conversion, protecting your data.

Conversion process

  1. Ensure you have a valid parity and a current backup of your flash drive.
  2. Enter Maintenance Mode from the Main tab.
  3. Replace and rebuild your parity drive first.
  4. Swap out each data drive one at a time, rebuilding the array after each replacement.
  5. The new drive will be formatted with the appropriate partitioning style based on its size:
    • 2TB or smaller: Uses MBR partitioning
    • Larger than 2TB: Uses GPT partitioning
  6. Once all drives are replaced and rebuilt, exit Maintenance Mode.

This process keeps your data safe while changing the partitioning style.

Additional notes
  • Partitioning is automatic: Unraid automatically chooses the partitioning style based on drive size:
    • 2TB or smaller: Always uses MBR partitioning
    • Larger than 2TB: Always uses GPT partitioning
  • Starting with Unraid OS 6.9, partition 1 starts at 32KiB for rotational devices and 1MiB for non-rotational devices, regardless of the partition style.
  • Always back up your flash drive before starting this conversion process.

Networking​

Is there any way to disable the br0 bridge?
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Yes. The br0 bridge is a Linux network bridge allowing Docker containers and VMs to connect directly to your local area network (LAN) with their IP addresses. It acts as a virtual network switch that connects your physical network interface to the virtual interfaces used by containers and VMs.

note

Disabling br0 means that VMs and Docker containers will not have direct access to the LAN and may lose some advanced networking features.


I can't seem to connect to the WebGUI using http://tower or http://tower.local. What do I do?
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If you're having trouble connecting to the WebGUI by hostname, the issue might be with your local DNS not resolving the server name. Instead, try connecting directly using the IP address.

How to find your server's IP address:

  • Check your router or switch's DHCP client list for a device listed as "Tower" or something similar.
  • If you assigned a static IP during flash creation, use that address.
  • Plug in a monitor and keyboard to your server; the IP address will appear on the local console after it boots.

Common causes for this issue:

  • Your computer and server might be on different subnets or VLANs.
  • Your router may not support local hostname resolution.
  • The Unraid server might not be connected to the network or have a misconfigured network setting.
  • Firewall or security software may be blocking access.

If you are unable to connect, try rebooting your server and network equipment, and ensure that all cables are securely connected.


Installation​

I can't get the USB flash creator to install Unraid on my flash device. What do I do?
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If the USB flash creator tool isn't working for your system or flash drive, you can utilize the manual installation method to prepare your Unraid boot device. This method is compatible with Windows, macOS, and Debian/Ubuntu Linux.


I need to configure my system to boot using UEFI. How do I do this?
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You can set up UEFI boot mode in a few different ways:

Option 1: During flash creation

  • When using the USB flash creator, select the option to enable UEFI boot mode before writing Unraid to the flash drive.

Option 2: After booting in Legacy Mode

  • In the WebGUI, head to the Flash Device Settings → Flash Device page.
  • Enable UEFI boot mode and reboot your server.

Option 3: Manual folder rename

  • On the flash drive, rename the EFI- folder to EFI (remove the dash -).
  • Insert the flash drive into your server, then enter your motherboard BIOS/UEFI settings.
  • Set the USB flash as the primary boot device and enable UEFI boot mode (be sure to disable CSM/Legacy/Compatibility mode, if available).

I'm having issues using my web browser with the WebGUI. What can I do?
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If you're encountering display or functionality issues with the WebGUI, consider the following:

  • Ad-blockers and content blockers: These browser extensions may interfere with the WebGUI. Try adding your Unraid server to your ad-blocker's whitelist or disabling the blocker for your server's address.
  • Browser extensions: Some extensions could block scripts or alter page content. Disable extensions or try using a private/incognito window.
  • Outdated browsers: Ensure you use a modern, up-to-date browser (like Chrome, Firefox, or Edge). Older browsers may not fully support the WebGUI.
  • Cache issues: Clear your browser cache or try a hard refresh (Ctrl+F5 or Cmd+Shift+R).
  • Network issues: Ensure that your computer and server are connected to the same network and subnet.

If problems persist, try accessing the WebGUI from another browser or device.


How do I extend my Unraid trial?
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If you need more time with your 30-day free trial of Unraid, you can extend it. Once your original trial expires, stop the array and go to the Registration page. You should see a button that allows you to request a 15-day extension. You can do this twice for a total of 60 days before you need to purchase a license.

important

You must use the same USB flash device to continue your trial. Changing the flash device will require starting a new trial from scratch.