Cura Version
main
Operating System
Debian Linux sid
Printer
N/A
Reproduction steps
- Run Cura with a system-installed copy of numpy that is at least version 2.3.0
- Load a project, slice and open the preview
Actual results
Cura stops rendering the UI, and the following message is printed on the terminal:
2026-02-20 21:31:49,148 - DEBUG - [MainThread] UM.View.GL.ShaderProgram.load [61]: Loading [/usr/lib/cura/plugins/SimulationView/simulationview_composite.shader]...
2026-02-20 21:31:49,195 - DEBUG - [JobQueueWorker [3]] CuraEngineBackend.ProcessSlicedLayersJob.run [74]: Processing new layer for build plate 0...
2026-02-20 21:31:49,280 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: Exception: Job <CuraEngineBackend.ProcessSlicedLayersJob.ProcessSlicedLayersJob object at 0x7f779f15fa10> caused an exception on worker JobQueueWorker [3]
2026-02-20 21:31:49,281 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: Traceback (most recent call last):
2026-02-20 21:31:49,281 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: File "/usr/lib/python3/dist-packages/UM/JobQueue.py", line 133, in run
2026-02-20 21:31:49,282 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: job.run()
2026-02-20 21:31:49,282 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: ~~~~~~~^^
2026-02-20 21:31:49,282 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: File "/usr/lib/cura/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py", line 143, in run
2026-02-20 21:31:49,283 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: line_types = numpy.fromstring(polygon.line_type, dtype = "u1") # Convert bytearray to numpy array
2026-02-20 21:31:49,283 - ERROR - [JobQueueWorker [3]] UM.JobQueue.run [135]: ValueError: The binary mode of fromstring is removed, use frombuffer instead
beginResetModel called on OutputDevicesModel(0x2c490720) without calling endResetModel first
endResetModel called on OutputDevicesModel(0x2c490720) without calling beginResetModel first
Expected results
No ValueError is generated.
Add your .zip and screenshots here ⬇️
This issue was reported on the Debian bug tracker: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1121290#15
We're still on Cura 5.0.0, but the issue hasn't been fixed in the main branch: https://github.com/Ultimaker/Cura/blob/main/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py#L143
References from the numpy documentation:
The deprecation has been present since numpy 1.14: https://numpy.org/doc/stable/reference/generated/numpy.fromstring.html
And it started generating ValueErrors in 2.3.0: https://numpy.org/doc/stable/release/2.3.0-notes.html#expired-deprecations
A fix should be relatively trivial, and it should also work fine with older numpy versions:
Replace all lines that use fromstring like this:
line_types = numpy.fromstring(polygon.line_type, dtype = "u1") # Convert bytearray to numpy array
with:
line_types = numpy.frombuffer(polygon.line_type, dtype = "u1") # Convert bytearray to numpy array
The same issue exists in https://github.com/Ultimaker/Cura/blob/main/plugins/3MFReader/ThreeMFReader.py#L140 and https://github.com/Ultimaker/Uranium/blob/main/UM/View/GL/OpenGL.py#L296
Cura Version
main
Operating System
Debian Linux sid
Printer
N/A
Reproduction steps
Actual results
Cura stops rendering the UI, and the following message is printed on the terminal:
Expected results
No ValueError is generated.
Add your .zip and screenshots here ⬇️
This issue was reported on the Debian bug tracker: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1121290#15
We're still on Cura 5.0.0, but the issue hasn't been fixed in the main branch: https://github.com/Ultimaker/Cura/blob/main/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py#L143
References from the numpy documentation:
The deprecation has been present since numpy 1.14: https://numpy.org/doc/stable/reference/generated/numpy.fromstring.html
And it started generating ValueErrors in 2.3.0: https://numpy.org/doc/stable/release/2.3.0-notes.html#expired-deprecations
A fix should be relatively trivial, and it should also work fine with older numpy versions:
Replace all lines that use fromstring like this:
with:
The same issue exists in https://github.com/Ultimaker/Cura/blob/main/plugins/3MFReader/ThreeMFReader.py#L140 and https://github.com/Ultimaker/Uranium/blob/main/UM/View/GL/OpenGL.py#L296