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This should be stickied, be cause it has come up before and will come up again: Cura has a new setting named Initial Layer Temperature which defaults to the normal temperature +5. This is only for the first layer.

Bro-tip: if you reply to a 1.5 year old thread with a new issue, we won't know if we can believe you when you say you installed the latest version. The latest version at the time of writing is Cura 2.4 (not 2.4 beta).

Cura 15.x = "Legacy Cura", the original Cura software, not in active development since 2015 *by Ultimaker* To make matters more confusing, other companies like eg Lulzbot continued working on the old Cura, and reached versions like Cura 21.something. Yet others continued working on old Cura and called it Cura 1.5. But Cura 2.x is the way forward.

They should be automatically upgraded to 2.4. Note that this also means that they wont work with 2.3 anymore. So make a backup.

Cura 2.5 will let you (view and) print gcode files.

Specifically, {print_bed_temperature} has become {material_bed_temperature}, {print_temperature} has become {material_print_temperature} and {travel_speed} has become {speed_travel}. The reasoning for the new names is that they all start with the category.

The thing may be that Cura now needs a newer version of these redistributables, which may not install successfully on systems that don't have this particular windows update: https://support.microsoft.com/en-us/help/2999226/update-for-universal-c-runtime-in-windows At least, that's how I read it.

There's a new setting called "Initial Layer Temperature" which defaults to the normal temp +5. Also see https://ultimaker.com/en/community/38321-24-beta-2-nozzle-temperature-bug

Post the plugin somewhere, and somebody may be able to help.

The next version of Cura is going to need the same windows update. Any reason in particular not to keep your Windows version up to date?

I agree with you that it would be much nicer if there were an easier way to switch between versions. It has been brought up before, but it has not gotten any developer time sofar. Note: I'm just the messenger here. Best I can do is tell people to make a backup of their configuration folder before trying a new version.

As far as I can see, there have been no changes in the UMO/UMO+ definitions between version 2.3.1 and 2.4.

This is a known issue / by design. If Cura detects files from an older version, it backs them up into folders marked "old" and upgrades them. There is no automatic "downgrade" functionality. This means you can no longer go back a version without manually restoring files from these "old" folders.

Good catch. I have updated my gist with a *much* simpler version that also fixes this issue.

Sorry for the broken link, and thanks @tinkergnome for posting the correct one. I have edited my post above. Note that I don't have a UM3 myself, so I have not tested the definition. If you try it please report if it works.

Note that it is likely that a future version of Cura 2.x will have better support for USB printing again, even if Ultimaker is not working on it. Cura is open source, and other developers are working on it as well, eg the people behind the Lulzbot TAZ printers.

You can try PrintRun (http://www.pronterface.com/). Or you could even use legacy cura to load the gcode produced with Cura 2.x and send it to your printer.

See the readme for the PPA: https://launchpad.net/~thopiekar/+archive/ubuntu/cura There's a separate PPA that includes the plugins. Note that the PPA is not officially supported by Ultimaker, the AppImage is.

Perhaps a screenshot?

c'est compliqué A potential untested workaround is to add a UM3 definition to Cura that forces it to regard the UM3 as a single extrusion printer. You won't have dual extrusion, but you will have One at a Time printing. Here is such a definition: https://gist.github.com/fieldOfView/bde7189087721451784865a28f3fc2c1 Place it inside the "definitions" folder either in your Cura application folder or in the "definitions" folder inside your configuration folder. You would then create a new printer inside Cura and pick the "Ultimaker 3 single extrusion" printer definition. You can have both an "Ultimaker 3" and an "Ultimaker 3 single extrusion" printer connected to the same physical printer in Cura, so you can then choose between single extrusion prints that allow One at a Time, and dual extrusion prints that don't. (My french is not great) (edit: and neither are my copy/paste skills)

This answer seems to be the right (and safe) thing to do to fix it on your end: http://stackoverflow.com/a/33274879 A future release will likely fix it by including pretty much the same thing (visual c++ redistributables), but you would have to wait for that and I don't know how long you would be waiting.

There is one hack you can try: In your Cura folder, find the file plugins/USBPrinting/USBPrinterOutputDeviceManager.py It should look like this: https://github.com/Ultimaker/Cura/blob/2.4/plugins/USBPrinting/USBPrinterOutputDeviceManager.py#L89 Change line 85 to this (ie: change True to False, change nothing else) result = self.getSerialPortList(only_list_usb = False) Be careful not to change the indentation! Now restart Cura and it might detect your printer. Let us know if it does. If Cura still doesn't detect your printer, then unfortunately you will have to use another tool to send the gcode to your printer.

It is unfortunate that this was chosen as best answer, as it disables the setting for other (single extrusion) printers. If you really want to go the "I don't care if it can break my printer, I want my One at a Time back!" route, make that line say "enabled": true, A potentially better and certainly safer, but untested solution (because I don't have a UM3) is to add a UM3 definition to Cura that forces it to regard the UM3 as a single extrusion printer. You won't have dual extrusion, but you will have One at a Time printing. Here is such a definition: https://gist.github.com/fieldOfView/bde7189087721451784865a28f3fc2c1 Place it inside the "definitions" folder either in your Cura application folder or in the "definitions" folder inside your configuration folder. PS: no need to call devs rude when they are trying to help while at the same time trying to make sure that people don't break their printers.

A better option is available: Use the UM2 (or UM2+) profile, but set the gcode flavor to "Reprap (Marlin/Sprinter)" in Machine Settings. This lets you edit start/end gcode, as well as set the material you want to use from Cura (overriding the settings on the printer, because these are ignored when printing over USB).

In your configuration folder (accessible through Help -> Show Configuration Folder) there should be a stderr.log