Fix “new_disprd failed” Error in DisplayCAL
You click “Calibrate and profile”, the instrument initializes, and DisplayCAL aborts with an error mentioning new_disprd failed. This error comes from dispread, the ArgyllCMS tool DisplayCAL uses to take measurements. It means ArgyllCMS could not open a working communication channel to your colorimeter. The measurement never started, so your profiles and settings are not the problem. The driver and USB layer is.
The Troubleshooting Chain (In Order)
1. Check Device Manager (Windows)
Open Device Manager and look for your instrument. It should be under Argyll libusb-win32 devices. If it appears under the manufacturer’s name instead (X-Rite, Calibrite, Datacolor), the Argyll driver is not bound, and that is your problem. In DisplayCAL go to Tools, then Instrument, then Install ArgyllCMS instrument drivers, or run ArgyllCMS_install_USB.exe as administrator.
2. Change the USB Port and Cable
Unplug from any dock, hub, or monitor USB passthrough and connect directly to the computer. Try a different cable. USB signal issues manifest exactly like this error, and users report this step resolving it.
3. Reinstall the Argyll USB Driver with Zadig
If the bundled installer fails (Windows driver signature enforcement is the usual cause), use Zadig to manually set the instrument’s driver to libusb-win32. Steps are in our quickstart guide.
4. Reinstall ArgyllCMS Itself
A corrupted or mixed ArgyllCMS install (for example old DLLs next to new ones) can also break dispread. Remove the old ArgyllCMS folder completely, install current ArgyllCMS 3.5.0 fresh from our ArgyllCMS page, and point DisplayCAL at the new bin folder (File, then Locate ArgyllCMS executables).
5. One Instrument at a Time
Disconnect every other measurement device. Multiple instruments, especially similar models, can confuse driver binding (see also issue #304).
6. Linux: Permissions
On Linux this error usually means your user cannot open the USB device: join the plugdev group, install udev rules, reconnect. Details in our Linux guide.
Still Failing?
- Isolate hardware vs software: test the meter in the vendor’s own app. Dead there means cable, port, or meter.
- Read the full log. DisplayCAL’s log window shows dispread’s exact complaint. “Access denied”, “device not found”, and “open failed” point at different layers.
- Ask with data. Open a GitHub issue with your OS, DisplayCAL version, ArgyllCMS version, instrument model, and the full error text.
How to Read the Error Log
DisplayCAL shows a log window during measurements. When dispread fails, scroll up and look for the lines just before the failure. Phrases mentioning access, permissions, or the device not being found point at the driver layer (steps 1 to 3 above). Mentions of missing files or wrong paths point at the ArgyllCMS installation itself (step 4). Copy the full error text when asking for help. A report that says “it does not work” without the log rarely gets a useful answer.
Preventing It Next Time
- Keep one ArgyllCMS install. Problems often start when an old ArgyllCMS folder lingers next to a new one and DisplayCAL points at the wrong
bindirectory. - Do not let Windows Update replace the driver. After major Windows updates, check Device Manager. If the instrument moved out of the Argyll device group, reinstall the Argyll driver.
- Label your working port. If one USB port works reliably, keep using it. USB controller quirks differ per port.
Quick Checklist Before You Start Over
Before reinstalling anything, run through this sixty-second checklist: is the meter firmly plugged into a rear motherboard USB port, is any other measurement software closed, does Device Manager show the instrument under the Argyll group, and is DisplayCAL pointed at the correct ArgyllCMS bin folder? Users report that a surprising share of “new_disprd failed” cases are resolved by one of these four checks, no reinstall needed.
Related: DisplayCAL troubleshooting hub | Instrument not detected: 8 fixes | Quickstart guide