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Cura 3.2.21 is unusable

Posted: Wed Jul 04, 2018 5:05 pm
by bentwookie
I installed 3.2.21 on my Mac, paired with a Taz 6. It's so slow as to be completely unusable. Cura has never been fast, but it takes 10 seconds to pick a material and have the menu redraw now.

I took a sample and QT is calling into Python as fast as it can, over and over again on the main thread.

QT and Python...

Anyway. Anyone else seeing this?

edit: Cura/not Cuba, though Cuba isn't particularly face paced either :)

Re: Cura 3.2.21 is unusable

Posted: Thu Jul 05, 2018 3:53 am
by jlund
I see 10s including re-slicing when changing material on a MacBook Core M7 8GB ram.

I guess it *can* be used, but we have unexpectedly used weeks on a flexy dually V2 setup for our Taz6, where none of the suggested steps really worked, from calibration, to test print to slicer profile handling and slicer features for dual setup.

While I appreciate the time an energy put into a very difficult challenge - I really do - it is a frustrating user experience.

Re: Cura 3.2.21 is unusable

Posted: Thu Jul 05, 2018 7:31 am
by Brent.I
From what you are describing, it sounds like you could have some old incompatible profiles causing the lag. Be sure to follow the Uninstall and Clear Cache directions for your specific operating system. Directions can be found here:

If you are still having issues, please reach out to and we will see what we can find.

Re: Cura 3.2.21 is unusable

Posted: Thu Jul 05, 2018 10:44 pm
by bentwookie
This "clear your caches" thing is a pretty blunt hammer. I blindly followed that advice the for the last major version and was rewarded by losing all of my material profiles.

Maybe instead of asking customers to root around your cache directories over and over, you fix your versioning.

I reached out to support and am going back to 21.08.

Re: Cura 3.2.21 is unusable

Posted: Fri Jul 06, 2018 10:00 am
by b-morgan
Someone will correct me if I'm wrong but I'm pretty sure 21.08 and 3.2.21 don't share any information.

Re: Cura 3.2.21 is unusable

Posted: Fri Jul 06, 2018 2:22 pm
by CB_HK
Joined the forum to add that I’m having the exact same issues. Even went so far as to remove all remnants of Cura from my computer before doing a fresh install. I lost my profiles but I knew that would happen head of time (and frankly not a huge issue as I’m only using two materials).

Either way, it’s definitely an issue and it makes Cura unusable for anything. Hopefully a fix is on the way.

Re: Cura 3.2.21 is unusable

Posted: Fri Jul 06, 2018 5:38 pm
by bentwookie
21.08 writes to ~/Library/Application Support/Cura and 2.6.xx/3.2.xx write to ~/L/AS/cura-lulzbot. All of them write to version specific directories inside their base directory, so either this cache versioning thing is bunk, or something is reading from the wrong place. Regardless, the "clear your caches" mantra has been going on for more than a year now.

I turfed it all and 21.08/ is working as well as it ever did. Happy to be printing agin.

Re: Cura 3.2.21 is unusable

Posted: Sat Jul 07, 2018 11:44 am
by b-morgan
A cache conflict potentially occurs when the newer version picks up printers and profiles from the previous version.

The potential problem is apparently caused because each version of Cura may add, subtract, or change the meaning of its internal data structures but doesn't have any version control and therefore can't map old data structures into new data structures.

It is, IMO, a poor design but apparently not one which the developers are willing to fix. At the very least, they should remove the code that looks at any version other than the current one.

Re: Cura 3.2.21 is unusable

Posted: Mon Sep 24, 2018 10:53 am
by wyostargazer
I've done the uninstall and cache-clearing ghost dance several times, and my install of everything from 3.2.21 until the present 3.2.23 has been unusably laggy- 3 second delays even for camera rotation or data entry. I'm also seeing utter failures in re-scaling, lay flat commands, and z-height defaults on load or re-size. Worse, after object have been placed back at Z0 (or even above!), they will remain unsliceable because they don't fit within build volume!
This is a Taz4 and the model is a 4cm long cat, so an oversize error seems unlikely.

Anyone have luck disabling plugins or otherwise speeding things up? Other major errors like this?

Re: Cura 3.2.21 is unusable

Posted: Mon Sep 24, 2018 11:24 am
by bentwookie
Download an older Cura (21.08) and match your printer's firmware to it. Until the notification of your reply reminded me, I'd forgotten what a slow-motion mess 3.2.x was. I'm happy to have nothing to do with it.