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

I am printing a large object for 2 days now. Im noticing some large ridges and noticeable imperfections. Curious what settings i should be looking at to ensure these are removed? Is there something obvious Im missing?

In my case, it has produces a very prnounced X-Y layer shift:

It has worked fine in the past, this is the first time I have noticed. This is a multi-part print and all the parts showed identical layer shift. All heads where calibrated when the printer was setup and nothing has changed since then (at least intentionally).

Any ideas besides "Try running the X-Y calibration again?".

Thanks.

How do i overcome this? I wish to enforce "max volumetric speed" also on wipe tower. Or any gcode patch...

I have calibrated temp (235c) and speed (10mm3/s) for this addnorth rPETG. On stock nozzles.

"Extra flow for purging" not possible to set under 100% ?

Adjusted wipe tower accel control down to 250 it got better, but still fraying in the center and way to slow for production.

There are another post on the same subject with no replies. https://forum.prusa3d.com/forum/english-forum-general-discussion-announcements-and-releases/how-to-create-custom-g-code-to-modify-the-print-speed-for-the-wipe-tower-for-multi-material-prints/#post-336277

Thanks for reading, have a nice day.

I’m trying to flash firmware to my MMU2S for the first time, but the control board is not detected. RAMBo flashes fine, but MMU2S shows:

“MMU 2.0 Control device was not found (VID/PID 0x2c99/3 or 0x2c99/4)”

I tried reset button, different USB ports, and both Windows/Linux, but still no luck.

Has anyone fixed this issue before? Any suggestions?

Thank so much! Help me!