RE:
Identical issue in 6.4.0.
XL 5TH. I have 2 that I bought at the same time within the last month, and one of them (so far) simply stops mid-print with no error after hours, and just stays in its current state without cooling down, powering off, or anything, indefinitely.
Happened so far on 3 separate files sliced in Prusa Slicer.
All 3 times appear to have been when the next instruction was a tool change.
If I press pause, the LCD works, but goes into a "pausing" state and never actually pauses, and nothing else can be done. No USB communication error or anything in my case. Removing and re-plugging the USB does nothing. 2 of the 3 times, if I pressed pause, then power cycled the machine, it did resume.
Support suggested I downgrade firmware, and when I showed them this thread, they stuck to their guns *shrug*. Could be a bunch of different root causes creating similar situations I suppose, so I'll try the firmware downgrade, but not optimistic.
Just chiming in to say that this has started happening to me in the last few days. I've just updated to the latest firmware (6.4.0+11974).
The first couple of times, I tried the Pause button, but then the interface froze. So I scrapped the job and started again.
The third time, I came searching and found this thread. Thanks everyone - the process of switching the machine off briefly at the power point to perform a power panic worked for me. I'm now 82% through a 26-hour job, having had to go through the process three times so far on this one job. Luckily, each time it's happened, I've "fixed" it before everything cooled down. Fingers crossed...
This job is a two-filament job on a 5TH machine. When I do the power panic, it re-homes and then changes to next filament. I can't quite tell if that means it's stopping at that point of a filament change, or whether the power panic induces a change. But the toolhead has stopped in the same position every time this has happened (five times so far).
This has never happened in the previous year of using the machine (lightly). Who knows why it suddenly started happening.
RE: Prusa XL stops mid print with no errors / warnings
This happens to me as well on long running prints, two tool heads, usually past 18 hours of printing. The only thing that works is turning the Prusa XL on and off with the switch.
However, the part that really irks me is that each time, it results in a sizable layer shift of the whole model, followed by other layer defects as a result. For that matter, I may as well just stop the print, and reprint a second piece and glue it on.
Incidentally, I just downgraded firmware to 6.2.6 for other reasons, and did a new test of the rocket ship thing. Same issue, at about 24 hours.
Identical issue in 6.4.0.
Support suggested I downgrade firmware, and when I showed them this thread, they stuck to their guns *shrug*.
As 6.4.0 has not been released for the XL and 6.2.6 is the latest stable release this seems eminently sensible.
This thread is full of users using alpha and beta software as if it was a stable release and complaining if they encountered a bug: surprise surprise, alpha and beta software are test releases intended for keen users to try-out and bug-hunt. The correct procedure on finding a bug is to report it to the developers, Prusa in this case via their github, and then to revert to the latest *stable* release while the devs act on the report and incorporate the fixes into the *next* stable release.
...and that's what some of the more sensible users in this thread report that they have done, successfully.
Cheerio,
RE: Prusa XL stops mid print with no errors / warnings
Since Nov 25,2025, 6.4.0 is the recommended firmware from Prusa for the XL. My XL keeps reminding me every day since I've downgraded back to 6.2.6 😉
RE: Prusa XL stops mid print with no errors / warnings
My XL keeps reminding me every day since I've downgraded back to 6.2.6 😉
😆 😆 😆
I voluntarily and immediately reinstalled 6.2.6 after a veritable flood of failures, messages, and red displays appeared.So far, it is purring quietly and reliably with 6.2.6.
RE: Prusa XL stops mid print with no errors / warnings
Since Nov 25,2025, 6.4.0 is the recommended firmware from Prusa for the XL.
Curious. If you follow the links (from the top of this page) Software > Drivers and Firmware > XL you arrive at Firmware 6.2.6
- and I have never been prompted to update to 6.4.0
So: I stand corrected - in part; much of this thread is complaints about alpha and beta software so my main point still stands.
Now I suppose I need to investigate why.
Cheerio,
RE: Prusa XL stops mid print with no errors / warnings
This is happening to enough of us on officially-supported firmware that your point isn't really relevant, I think.