Cloud Sync Overwriting Local Profiles – Root Cause and Fix

Bambu Lab Software Bambu Studio
1

I ran into a very annoying issue with Bambu Lab Studio and its cloud sync feature.
Old profiles were repeatedly downloaded from the cloud and overwrote my recently updated settings — even though they had been saved correctly.

If you experience the same, check the corresponding .json files for your filament or process settings.
In my case, the problem was caused by invalid entries like these:

"default_acceleration": [
    "5000",
    "1200",
    "nil",
    "1200"
],

"gap_infill_speed": [
    "80",
    "40",
    "nil",
    "40"
],

Those "nil" values seem to make the sync go haywire, forcing Studio to restore outdated settings from the cloud for any section containing them.

:white_check_mark: How I Fixed It

  1. Turn off cloud sync
    Go to Settings → Cloud Sync and temporarily disable automatic synchronization.
  2. Open the affected .json file
    Use a text editor and replace inconsistent entries with uniform values, for example:
"default_acceleration": [
    "1200",
    "1200",
    "1200",
    "1200"
],

"gap_infill_speed": [
    "40",
    "40",
    "40",
    "40"
],
  1. Save the file and reopen Bambu Lab Studio
  2. Re-enable cloud sync
    Once done, enable cloud synchronization again.
  3. Verify the fix
    Open the corresponding .info file for that profile and look for an updated timestamp, for example:
sync_info =
updated_time = 1760580704

Not sure why this happened — the files were never edited manually — but the revert occurred silently in the background.
I only noticed it after a 14-hour print failed because all speed settings were suddenly back to defaults, far beyond what the filament could handle.

Hopefully this helps anyone else running into the same frustrating issue.

EDIT: This seems to occur when changing any of the standard speed fields, on every profile I done this I get a corrupted .json-file

1 Like
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2

Sometimes I genuinely question if Bambu Lab Support has any internal quality control at all.

I provided a fully reproducible method to trigger this issue — it cannot fail — yet the only response they managed to come up with was the usual “please make a video.”

This is exactly the same amateur routine as when they once asked me to deliberately cause a head crash to “show what happens.” The result? A destroyed build plate and nozzle — and of course, zero compensation.

Keep that in mind when you throw money at the next “revolutionary” product like the H2C and expect serious support.

You won’t get it.

They will ask you to destroy your hardware, waste your time, and then politely deny every responsibility afterwards.

Dear Bambu Lab 3D printer user:
​Hello!We sincerely apologize for the inconvenience you have experienced.
​Could you please record a video showing the entire process you described below?“Save a perfectly calibrated process with your exact speed values.
​Confirm it loads correctly in a new project.
​Close Studio completely and restart it.
​Result: every single speed value is reset to what appears to be Bambu Lab’s default settings.”We performed the same operations in the latest version of Bambu Studio but were unable to reproduce the behavior you mentioned.
​Please record a video of the full process and, following the instructions in the attached tutorial, upload the Bambu Studio log files to this ticket as well.Export Bambu PC software log | Bambu Lab Wiki Once we receive more detailed information, we will forward it to our R&D department for further analysis to identify the root cause and provide a suitable solution. Thank you very much for your patience and support!Best regards,
​Bambu Lab Customer Support

4

In my case, the system quietly reverted multiple settings to internal defaults without showing any indication that it had done so. I launched a 14-hour print fully expecting the profile to be honoured, only to discover that none of the configured parameters were used. The first time it happened, I assumed I had made a mistake. The second time, the moment Studio attempted to sync, every overwritten value lit up in red as if the software was eager to demonstrate just how unreliable it can be.

What makes this even more frustrating is that Bambu Lab seems perfectly content leaving this behaviour unresolved. I can reproduce it on demand:
— create a new profile
— save
— let it sync
— adjust the speed parameters for the left nozzle
— save
— adjust the parameters for the right nozzle
— close Studio
and the instant it syncs, the profile is corrupted again. This is not an occasional glitch. This is predictable, repeatable failure.

And yes, of course I know how to back up my settings — but the fact that users are forced to back up every minor adjustment simply to protect themselves from a sync mechanism that collapses under its own weight says everything. A synchronisation system that needs manual safeguarding after every change isn’t a feature; it’s a liability.

It also raises a bigger question: how many users are affected without realising it? How many people assume they “forgot to save” or “clicked the wrong field,” when in reality the sync system quietly overwrote their settings behind the scenes? I would expect the real number to be significantly higher than anyone admits, because the failure is silent and leaves no trace unless you already know what to look for.

Support’s position doesn’t improve matters. Nothing will be addressed until a video is provided, despite the issue being trivially reproducible. In the meantime, manually repairing corrupted profiles in a text editor is an exhausting task, especially for anyone maintaining a large library of customised profiles.

This isn’t an isolated annoyance. It fits a growing pattern: development issues and gaps in QA are continually pushed onto the user to diagnose, document and prove. The support responses feel generic and dismissive, written as if the customer has no technical background at all, rather than addressing users who have invested heavily in the company’s ecosystem.

And speaking only for myself — this disappointment is coming from someone who once defended Bambu Lab and many of their decisions. At this point, it has become extremely difficult to justify that stance. When a company repeatedly shifts responsibility for its own systemic faults onto its customers and treats this as normal procedure, it becomes increasingly difficult to view the platform as reliable. Eventually, continuing to rely on products built on such fragile foundations stops making sense.

5

its funny, mods keep deleting my post because they dont like the fact I have proven users wrong on this site, I had this issue with my P2S, I deleted and created the profiles again, seemed to fix the issue for me.

A number of forum users, including moderators keep telling me I had a dirty bed, when my profile was being ignored because of Bambus last forced update.

1 Like
6

Support claims they cannot reproduce this, even though I have provided all logs, a video clip, and a completely bulletproof method to recreate the problem. They now expect me to spend another week restoring my profiles because of an internal error they caused.

Dear Bambu Lab 3D printer user:
Hello!

We are truly sorry for the inconvenience caused.

Thank you for providing the additional information. Regarding the issue you described, we have performed a reproduction test on our side, and unfortunately, we were unable to reproduce the same problem.

To ensure the accuracy of our verification, we repeated the test and recorded a corresponding video. We will attach this video to your ticket for your reference.

If the issue still occurs after performing the same operation, please provide a video of the process and upload it to this ticket. We do need this video to determine whether the problem is caused by an operational step or if there is indeed an abnormality in saving the filament profile. Only after confirming this can we determine whether it is necessary to submit the issue to our R&D team for further analysis.

We understand that this step may feel complex and time-consuming, but the information is essential for us to accurately identify the root cause. We truly appreciate your understanding and support.

Thank you for your support and patience!

Best regards,
Bambu Lab Customer Support

1 Like