Caja becomes unresponsive when I copy large files. It doesn't hang 100%, but it takes a very long time to open folders while copying (long enough that it becomes essentially unusable for the duration).
I've seen a lot of issues about the system freezing when copying large files, but that's not the case for me. The system is fine, it's just Caja.
Any idea what might be causing this or how to fix it?
Caja: 1.26.3
Ubuntu (MATE): 24.04.1 LTS
Hi, @Sagrafin and welcome to the Ubuntu MATE Community!
May be you find the following discussion useful
Thanks! But the transfer speed is fine. I do feel like the dialogue is not entirely accurate, and sometimes says it's finished when it really isn't (which has caused problems in the past).
But my problem here is that while copying, I can't browse folders because it takes a very long time to open a folder after clicking on it (while copying).
I noticed that last time I copied a large file that the 'progress bar' was not accurate. The progress bar was basically full, but the file was nowhere near finished transferring; however I don't believe I had any trouble with navigating in other Caja windows.
What kind of medium are you copying to?
USB flash devices (maybe some HDDs) can be notorious for this behaviour. I think to an analogy of roads and traffic.
This particular storage device is like a one lane road with traffic sharing that lane in both directions. 
Unless the folder was opened before (cached in memory), opening a different folder has to wait because that lane is occupied waiting for the large lorry of a file 
to get through first. There might be a free moment to sneak through in the other direction if it's able to get through, but it may have to wait much longer. Essentially, it's an synchronous operation, or maybe an I/O bottleneck.
→
"Open Folder" →
←←←←←
←←←←
When progress says 100%, it's like somebody saw the past by, driven by a 
(kernel) who'll continue reaching the destination in the background. At that point, unplugging the USB is like collapsing the road and letting it fall off a cliff. 
This is more like an asynchronous operation.
Not sure what the defaults are, but if it's bothersome, you could manually change the mount options to force sync or async. This article nicely sums up the two modes:
I'd personally just leave the defaults and avoid using it while it's busy copying/ejecting. There's only one USB I rarely use for copying multiple Linux distros that has this bottlenecking behaviour.
What kind of medium are you copying to?
Good point! A NAS (mounted as nfs). I thought it affected all operations, but copying to a different HDD works fine. It's just copying to the NAS that's causing hangs.
I checked, and different file managers have the same issue, so it's not an issue in Caja. I'll check and see if async mounting is an option. Thanks so much!
// update: Mounting with -o async doesn't solve the issue. But it's good to know what causes the problem & that it's not an issue with caja.
One more point is that intense network traffic may cause significant CPU load and overall PC slowdown. You might want to verify that too.
I see that your issue is pretty much resolved, given that it was likely network related, but keep in mind that Caja was likely meant for a Desktop User moving small quantities of files around, and not massive "site management", for which rsync is currently the best solution for network based copying.
However, for internal disk-to-disk, when it is not a backup operation, I strongly recommend using
tar cf - . | ( cd "${target_dir}" ; tar xvpf - )