The same happens when I load the filament to the nozzle. This is working because I have selected the "standard nextruder". But unloading does not work.
Is there some configuration I need to modify?

Core One support issues: what 1,094 threads actually tell us

I pulled the full topic list from both Core One troubleshooting subforums (Assembly and first prints troubleshooting and Hardware, firmware and software help) — 1,094 unique threads, 11,518 posts, ~2.1M total views as of April 2026 — and classified every thread by issue type. Sharing the aggregate picture in case it's useful for anyone deciding between the kit and the factory-assembled unit, or just trying to anticipate where they're likely to spend time.

Caveats up front: title-only classification (I didn't read 11k posts), ~3% genuinely vague titles couldn't be classified, and there's no sales-figure denominator to turn these into rates per printer sold. This is a topic-volume distribution, not a failure-rate study.

Where the support volume actually goes

Two things jump out from the reply-weighted column:

• Print Quality is 7.5% of threads but 17.4% of replies — almost entirely because of VFA Artifacts on X+Y Straight Edges (1,286 posts). Strip that one thread and the category is roughly proportional.
• Calibration is 2.0% of threads but 6.7% of replies — mean 32.8 posts per thread, the highest of any category. Small-N, high-intensity, driven by threads like Failed Y-calibration of a new CoreOne (420 posts) and Constantly recalibrating (92 posts).

Motion/gantry is the single biggest category on every measure. This is where Core One owners spend the most time.

The Assembly vs Hardware subforum split — the clearest structural signal

This is the closest proxy I have for kit-leaning vs. factory-leaning populations, since most titles don't self-identify. The two subforums are used for very different stages of ownership, and the category mix reflects that:

Read it as: if you just finished assembling a kit, expect motion and bed/first-layer issues to dominate. If you've been running the printer for a while, firmware and enclosure/accessory issues become the dominant post-commissioning noise.

Extruder, electrical, and filament-handling issues are roughly evenly distributed — these don't care how the printer got assembled.

Kit vs factory: what I could actually extract

Only 6.4% of thread titles (70 of 1,094) contain an explicit kit-vs-factory keyword — the other 93.6% are unmarked without reading the thread body. So the following is a small-N qualitative signal, not a rate comparison.

Explicit signal: 52 kit-identified threads, 18 factory-identified threads.

Within each group, the dominant failure-mode cluster is clearly different:

Kit cluster (52 threads):

• 30.8% are MK3/MK4→CoreOne upgrade-specific failures — Y-axis self-test failures post-upgrade, Z-axis calibration failures, lead-screw travel mismatch between upgrade screws and Core One kit screws, POM-nut reuse warnings, "cables too short in the upgrade kit", "missing boxes in upgrade kit".
• 23.1% are assembly-step-specific problems — "Assembly step 4.30 rear trapezoidal nut", "Step 7 securing the rear motor", "Wrong part included in my kit", "Missing fuses", "Missing steps in the kit manual".
• 21.2% are motion issues on new builds — mostly Y-axis self-test failures.

Factory cluster (18 threads):

• 38.9% are out-of-box quality complaints — "Arrived damaged", "Brand new OUT OF THE BOX PRINTER ", "new assembled Core One - print lucks ugly", "Not the greatest unboxing experience", "New pre-assembled Core One stuck booting halfway", "Pre-assembled unit with extreme under-extrusion problems".
• Individual cases of shipped-with-bad-thermistor, shipped-with-layer-shifts-on-first-benchy, shipped-with-uneven-bed-temps, factory unit that decalibrates during print.

The clean distinction: both groups report Assembly/Build issues at high rates, but the cause is different. Kit threads describe assembly-process problems (step X, wrong part, manual error). Factory threads describe QC-at-delivery problems (arrived broken, bad thermistor, booting stuck, bed temp uneven, layer shifts on first print).

This is consistent with the expected failure modes of each channel — kits surface assembly errors, factory units surface QC escapes — but the fact that ~39% of the explicit-factory threads are out-of-box defect complaints is worth noting if you're evaluating the pre-assembled option. N is small (18), so take the percentage loosely; the qualitative pattern is clean.

The ten mega-threads driving a lot of the noise

If you read nothing else, these are the persistent issues on the Core One. Seven of ten are motion-adjacent.

The VFA thread alone has ~254k views — it's the single biggest gravity well in the Core One support landscape.

Method notes

• Scraped all pages of the two English-language troubleshooting subforums on 2026-04-21.
• 15-category keyword classifier applied to titles (iterated three times, 3.4% residual unclassified).
• "Answered" rate is 12.5% flagged across the dataset, but that's a floor — most resolved threads never get flagged.
• Excluded: General Discussion, How-do-I-print-this, User Mods, Signature Oak.

If anyone wants the raw JSON or the classifier to re-slice this a different way, happy to share. And if you spot miscategorizations in the mega-threads list or the kit/factory clusters, point them out — title-only classification has real blind spots.

mein Problem, es verstellt sich immer die Temperatur .

Beispiel: Ich möchte ABS drucken und wähle auch ABS aus, die Temperatur von Düse und Bett wird erreicht.

Dann setzt sich die Düsentemperatur automatisch immer auf 170 °C  und kühlt auch soweit ab und steigt dann erst wieder auf die gewünschte Temperatur.

Hat jemand eine Erklärung ?

Viele Grüße Stefan