AVD authentication issue: “RDP file URL formatted incorrectly” error message

AVD authentication issue: “RDP file URL formatted incorrectly” error message

Issue symptom:

When attempting to authenticate into AVD session, sometimes users may see an error message “RDP file URL formatted incorrectly “ which prevents them from accessing their AVD sessions. See screenshot below.

Affected NComputing products include:

  1. LEAF OS firmware version 3.3.5 and earlier
  1. RX420(RDP) and RX-RDP+ firmware version 3.3.5 and earlier


Root cause:

Microsoft recently changed the AVD redirection URL during retrieving of AVD workspaces. This change affected the previous LEAF OS and RX420(RDP)/RX-RDP+ implementation (version 3.3.5 and earlier). NComputing first observed the issue on April 28, 2022, and promptly generated hot fix releases for the affected products.


NComputing provided hot fix releases on May 1, 2022 which addressed the above AVD authentication issue. The hot fix releases include:

  1. LEAF OS (version 3.3.13)
  1. RX420(RDP) and RX-RDP+ thin client (version 3.3.12)

Both images can be downloaded from NComputing Software Download page: https://www.ncomputing.com/support/downloads

How to update firmware:

Firmware can be updated either manually or remotely via PMC Endpoint Manager:

Update manually:

There are several manual firmware update options including from an FTP, web server or connected USB memory stick. From the device’s Setup GUI, go to ‘Support’ tab to select your option.

(1)    To manually update firmware from FTP or web server, enter the URL where the firmware update package is stored and click the ‘update’ button. For convenience purposes, NComputing has provided the following HTTP URL which can be used for the firmware update (note the URL is case sens:

LEAF OS firmware update file (3.3.13): http://firmware.ncomputing.com/LEAFOS/LEAFOS-3.3.13.upd

RX420(RDP) and RX-RDP+ firmware update file (3.3.12): http://firmware.ncomputing.com/RX420/rx4x0-rdp-3.3.12.upd

(2)    To manually update firmware from a connected USB memory stick, connect a USB memory stick (which contains the new firmware update file), and select the ‘Update from the USB memory stick’ option.

Update remotely via PMC Endpoint Manager:

Alternatively, the LEAF OS, RX420(RDP) and RX-RDP+  firmware can be remotely updated via PMC Endpoint Manager Software (version 2.7.0 and higher). The firmware update will take less than 1-minute once the firmware is downloaded to the device. Please do not turn off your device during this time. Once the firmware update is complete, the device will reboot automatically.

To ensure smooth transition and uninterrupted management ability, NComputing suggests updating PMC to version 2.9.4 (latest version) before upgrading devices to LEAF OS version 3.3.13 and RX420(RDP)/RX-RDP+ version 3.3.12.

PMC 2.9.4 comes with the device configuration definitions for LEAFOS(x86) v.17, RX420(RDP) v.17 and RX-RDRDP+ v.13 already available.