Bugs & Errors - Prusa3D Forum

Files won't download to printer

cmpickle — Sun, 03 May 2026 19:55:27 +0000

I ran into an issue where I had my printer in a ready state and a file in the queue but the file just said "not downloaded to printer". I tried a bunch of things and uploading the file more times. It turned out that the problem was I had at one point uploaded a file a few times in succession that had the same name. This was because the prusa slicer uses the name of the project and so some files were named the same thing that weren't intended to. This was causing the error "file with that name already exists on the printer" on the dashboard view. I didn't notice that there for a long time as I was looking at the queue and files tab. I eventually found that and deleted those file transfers that had the same name and my files transferred correctly again. I think the printer shouldn't get stuck if you try to transfer files of the same name. It could append a unique identified like if you copy pasted a file with the same name would do or it could at least just fail the transfer outright without clogging up the file transfer queue. As it is it's a terrible user experience and was not at all obvious on what I needed to do to get files transferring again.

Old Removed Printers Cause Error message upon login when they are not found.

bryn51 — Tue, 21 Apr 2026 00:17:27 +0000

I once had 4 printers, but sold two of them. I removed them from prusa connect. But ever since that day, when I log in (web) to Prusa Connect, it comes up with several error popups "Error Printer not found or does not belong to the given user".

Clearly Prusa Connect hasn't got the memo about those printers and still thinks I have them, tries to find them in my list of current printers but faiis. I searched everywhere for a reference to those old printers to amend the list, but nothing. Seems clear that there is an error of logic in the opening screen code somewhere. Or a missing page that would allow the user to see and amend the list of affiliated printers with the current login. Or perhaps a deficiency that occurs when a printer is removed, not completely removing all related data. I'm just guessing.

Whatever is the cause I suggest that its annoying to users, and ought to get some attention.

"Printing time" is really "time on this tab"

André — Sat, 18 Apr 2026 11:27:41 +0000

This time is "how long you watch this tab,"

(you need to click the screenshots, this forum does a lousy job.)

switch to any other, like "print history" , and back:

if you open this well into a print, and see printing time <1m ... you know something is wrong.

Slicer crashes 100% of the time at Connect login

vtgearhead — Sun, 12 Apr 2026 16:35:15 +0000

Title says it. Under Ubuntu Linux 24.04 I see a dialog box referencing some new authentication scheme, followed by an immediate crash. 100% repeatable. Works on a Mac Mini running Sequoia, FWIW. Whatever new security layer this might be it doesn't play nicely.

P0: Slicer unuseable: 2026-04-10 11:50 am - Slicer broken, cors error

killakatze — Fri, 10 Apr 2026 09:54:04 +0000

Please fix the cors error, the slicer is 100% unuseable

manifest.webmanifest:1  Failed to load resource: the server responded with a status of 403 ()Understand this error
slice:1 Manifest fetch from https://www.printables.com/manifest.webmanifest failed, code 403Understand this error
manifest.webmanifest:1  Failed to load resource: the server responded with a status of 403 ()Understand this error
slice:1 Manifest fetch from https://www.printables.com/manifest.webmanifest failed, code 403Understand this error
 📤 External app message 
3 📩 External app event 
 Setting token to expire in 5197245.697975159 ms
 📩 External app event 
 Setting token to expire in 5197192.698001862 ms
pagead2.googlesyndication.com/ccm/collect?rcb=3&frm=0&ae=g&en=page_view&dl=https%3A%2F%2Fwww.printables.com%2Fslice&scrsrc=www.googletagmanager.com&rnd=970452239.1775814471&navt=r&npa=1&ep.ads_data_redaction=0&gdid=dY2Q2ZW&_tu=CA>m=45He6490h2v811757514za200zd811757514xea&gcs=G100&gcd=13q3q3q2q5l1&dma_cps=-&dma=1&tag_exp=0~115938465~115938468~117384405~118131808&apve=1&apvf=f&apvc=1&tft=1775814471065&tfd=1238:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
pagead2.googlesyndication.com/ccm/collect?rcb=3&frm=0&ae=g&en=page_view&dl=https%3A%2F%2Fwww.printables.com%2Fslice&scrsrc=www.googletagmanager.com&rnd=970452239.1775814471&navt=r&npa=1&ep.ads_data_redaction=0&gdid=dY2Q2ZW&_tu=CA>m=45He6490h2v811757514za200zd811757514xea&gcs=G100&gcd=13q3q3q2q5l1&dma_cps=-&dma=1&tag_exp=0~115938465~115938468~117384405~118131808&apve=1&apvf=f&apvc=1&tft=1775814471065&tfd=1238:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
region1.google-analytics.com/g/collect?v=2&tid=G-3HK7B7RT5V>m=45je6490h2v874122347z8811757514za20gzb811757514zd811757514&_p=1775814470970&gcs=G100&gcd=13q3qPq2q5l1&npa=1&dma_cps=-&dma=1&gdid=dY2Q2ZW&_eu=EAAAAGA&are=1&cid=23495164.1775814471&frm=0&ir=1&pscdl=denied&rcb=5&sr=1512x982&uaa=arm&uab=64&uafvl=Not%253AA-Brand%3B99.0.0.0%7CGoogle%2520Chrome%3B145.0.7632.110%7CChromium%3B145.0.7632.110&uam=&uamb=0&uap=macOS&uapv=15.7.4&uaw=0&ul=en-gb&_s=1&tag_exp=0~115938465~115938468~118442252&sid=1775814471&sct=1&seg=0&dl=https%3A%2F%2Fwww.printables.com%2Fslice&dt=EasyPrint%20%7C%20Printables.com&_tu=CA&en=page_view&_fv=1&_nsi=1&_ss=1&ep.event_name=page_view&tfd=1291:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
region1.google-analytics.com/g/collect?v=2&tid=G-65PWSTXL4S>m=45je6490h2v871191087z8811757514za20gzb811757514zd811757514&_p=1775814470970&gcs=G100&gcd=13q3qPq2q5l1&npa=1&dma_cps=-&dma=1&gdid=dY2Q2ZW&_eu=EAAAAGA&are=1&cid=23495164.1775814471&frm=0&ir=1&pscdl=denied&rcb=9&sr=1512x982&uaa=arm&uab=64&uafvl=Not%253AA-Brand%3B99.0.0.0%7CGoogle%2520Chrome%3B145.0.7632.110%7CChromium%3B145.0.7632.110&uam=&uamb=0&uap=macOS&uapv=15.7.4&uaw=0&ul=en-gb&_s=1&tag_exp=0~115938465~115938469~117266401~118131808&sid=1775814471&sct=1&seg=0&dl=https%3A%2F%2Fwww.printables.com%2Fslice&dt=EasyPrint%20%7C%20Printables.com&_tu=SA&en=page_view&_fv=1&_ss=1&ep.event_name=page_view&tfd=1310:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
pagead2.googlesyndication.com/ccm/collect?rcb=17&frm=0&ae=g&dl=https%3A%2F%2Fwww.printables.com%2Fslice&scrsrc=www.googletagmanager.com&rnd=970452239.1775814471&navt=r&npa=1&ep.ads_data_redaction=0&did=dY2Q2ZW&gdid=dY2Q2ZW&_tu=CA>m=45be6490h2v9116191347z8811757514za20gzb811757514zd811757514xea&gcs=G100&gcd=13q3qPq2q5l1&dma_cps=-&dma=1&tag_exp=0~115938465~115938469~117384406&apve=1&apvf=f&apvc=0&tids=AW-958555779&tid=AW-958555779&tft=1775814471195&tfd=1369:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
 Guest data expired, not restoring printers/projects
pagead2.googlesyndication.com/ccm/collect?rcb=17&frm=0&ae=g&dl=https%3A%2F%2Fwww.printables.com%2Fslice&scrsrc=www.googletagmanager.com&rnd=970452239.1775814471&navt=r&npa=1&ep.ads_data_redaction=0&did=dY2Q2ZW&gdid=dY2Q2ZW&_tu=CA>m=45be6490h2v9116191347z8811757514za20gzb811757514zd811757514xea&gcs=G100&gcd=13q3qPq2q5l1&dma_cps=-&dma=1&tag_exp=0~115938465~115938469~117384406&apve=1&apvf=f&apvc=0&tids=AW-958555779&tid=AW-958555779&tft=1775814471195&tfd=1369:1  Failed to load resource: net::ERR_BLOCKED_BY_CLIENTUnderstand this error
 Guest data expired, not restoring printers/projects
 AccountId 311493 sid='TV93_TR6r_5reNrUAb5f' joined their user room
249The resource  was preloaded using link preload but not used within a few seconds from the window's load event. Please make sure it has an appropriate `as` value and it is preloaded intentionally.Understand this warning
 EasyPrint Extension not detected
(anonymous) @ app.BjQHjwPD.js:13
(anonymous) @ Bom16hJ5.js:23
r @ app.BjQHjwPD.js:483Understand this warning
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/files/?page_size=30' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/files/?page_size=30:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:734 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/files/?page_size=30&used=0' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/files/?page_size=30&used=0:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:734 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/files/?page_size=30' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/files/?page_size=30:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:734 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/file/' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/file/:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:512 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
 📤 External app message 
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/project/' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/project/:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
2 📤 External app message 
Bom16hJ5.js:682 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1  GL_INVALID_OPERATION: glTexStorage2D: Texture is immutable.Understand this warning
5Bom16hJ5.js:682 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/projects/?page_size=20&search=&user_deleted=0' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/projects/?page_size=20&search=&user_deleted=0:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:734 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/projects/?page_size=20&search=&user_deleted=1' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/projects/?page_size=20&search=&user_deleted=1:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
slicer.printables.com/app?lang=en&theme=auto:1 Access to fetch at 'https://slicer-api.printables.com/api/profile/' from origin 'https://slicer.printables.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.Understand this error
slicer-api.printables.com/api/profile/:1  Failed to load resource: net::ERR_FAILEDUnderstand this error
Bom16hJ5.js:24 Uncaught (in promise) TypeError: Failed to fetch (slicer-api.printables.com)Understand this error
sentry.prusax.com/api/39/envelope/?sentry_version=7&sentry_key=c38a1591365aca6b5e335c6ac5f6286c&sentry_client=sentry.javascript.sveltekit%2F9.17.0:1  Failed to load resource: the server responded with a status of 400 ()Understand this error
app.2.BjasK4u4.js:5

Prusa Connect Preferences - Stated "Feedback form" doesn't exist

UjinDesign — Mon, 23 Mar 2026 18:26:10 +0000

Hi.

I just noticed that there is a new "Preferences" section on the Prusa Connect website. Here, there is a notice saying that feedback through the feedback form. See image. However... there is no feedback form? Or at least I cannot find it.

80906767-screenshot-from-2026-03-23-19-23-22.png

Time to sort Connect?

Mike01Hu — Thu, 19 Mar 2026 18:55:51 +0000

Prusa Connect is a pain if you stop a print via the PC and always has been with MK3/4/Core 1. It's clumsy in the way it handles the command and when deleting files in the printer, queue or wherever, requiring multiple digging through the tabs to get any sense, understanding strange warnings and often requiring attending the printer to kick it back into a sensible mode. Don't get me wrong, I like it and use it all the time, but stopping a print using Connect is always done with trepidation!

Common guys, let's see some action here, too!!!

Getting many false positive Attention notification in the Prusa Connect app

Nathaniel — Wed, 18 Mar 2026 12:36:13 +0000

I have a Core One + (6.4.0+11974) that is sending the "Attention" notification that states I need to investigate the printer in person. I have gotten 10+ of these notifications in the last 12 hours however the printer has not been printing in that time. It finished a job and since then has been sending regular attention notifications. An in person inspection doesn't reveal any issues and the printer is set to ready and the queue is empty. This creates a poor experience as I don't want to ignore the important "Attention needed" notifications however they are all false positives.

Prusa Connect app on Android

"Caret" symbol not recognized in WiFi password

Luuk — Fri, 13 Mar 2026 15:27:41 +0000

Printer: Prusa Core One

FW version: 6.4.0

I wanted to add my printer to my WiFi network using the wizard and NFC connection. I got audio confirmation everything was OK, however the wizard didn't progress.

Then I tried the manual way of filling out the WiFi password, however I was unable to find the caret symbol "^".

So I decided to update my WiFi password and replacing the caret symbol. Then the NFC process worked indeed.

Please accept the caret symbol or provide a warning that this symbol is not supported.

lost connect connection

rjb2222 — Tue, 03 Mar 2026 03:17:36 +0000

I lost my printers connection to the conect app. I looked in the printer settings and it is connected to my internet. I wonder to to recoonect the printer as I do like the conect app.