Comparing files/folders on BOX brings down the system

[DTC-tobin]

Hi everyone,

As the title says, when I use WinMerge to compare files or folders saved on Box, the process eventually stops my whole system, with a forced restart the only way to recover.

WinMerge version

2.16.44.0 (current as of this post)

Previous versions also exhibit the same behavior (but I'm not sure how far back; it used to work)

Box setup

Files are referenced through BOX drive, an app similar to OneDrive, where files appear in the file system like any other file. (Paths look like "c:\Users\user\BOX..."). Although files appear like they exist on the local file system, mostly they are not, but are downloaded as necessary.

Box Drive version: 2.42.213 (latest version as of this post)

Local OS and computer

I am running Windows 11 Pro, 23H2
The PC is a ThinkBook 13x G4, Intel Core Ultra 5 125H @ 1.20 GHz
16 GB RAM

What works/doesn't work

Comparisons work fine in the following configurations:

• Files and folders saved on the local drive
• Files and folders saved on a network share (over SMB)
• Files and folders saved on OneDrive (regardless of download status)
• Files through Box Drive when the files have been downloaded for offline access

Given the above, it appears that files on Box that have not been downloaded locally beforehand are what trigger the crash.

Symptoms

If I specify paths to files/folders on Box and start the comparison, the process appears to start--I see the list of files, and some details appear--but then WinMerge doesn't show the process progressing. For a while, the UI will look responsive: clicking on a file in the list highlights it, and toolbar icons show the hover state when I mouse over. However, within a minute or so the application goes into a busy state, with the spinning blue cursor.

Similarly, I can switch applications, but bit by bit other applications stop responding.

I can't launch new applications. If I start Task Manager before starting the WinMerge compare, Task Manager stops updating immediately.

Eventually, nothing responds, except for mouse movement.

Other info

This problem first showed up on a coworker's machine. They installed WinMerge, tried to do a comparison, but their machine froze and had to be restarted. This was a Windows 10 computer, but I don't have the specific OS or WinMerge version (this was over a year ago).

Previously, I had been able to do these comparisons with no problems. Comparison was slow if the files hadn't been downloaded (since files were being downloaded prior to comparison). But at some point I installed a new version of WinMerge and suffered the same problem. (I'm sorry, I didn't record which version I had and which I upgraded to!) The issue has been replicated on at least one other coworker's machine (Win10), but after this we stopped using WinMerge.

Wrap-up

Again, the issue appears to be caused by files accessed through Box Drive that have not been saved to the local computer. It's not universally a cloud-storage problem, since OneDrive works. I have not tested any other cloud-storage providers like DropBox.

Ideally, I'd like WinMerge to be updated so that I can compare files on Box Drive (Box is where we check data prior to delivery to clients, so I want to compare the actual data we are planning to send, rather than a copy somewhere else).

At the least, not crashing the whole computer would be nice. If WinMerge crashes or freezes, oh well. But forcing a restart is obviously quite bad, as people will lose unsaved work.

Follow-up

I went back in time and downloaded the last 2.15.x release as well as the earliest release available on GitHub (2.14.0). Neither version did the comparison.

• 2.15.x froze the whole computer
• With 2.14.0, the app froze, but I didn't take down the whole computer; I could force-quit with Task Manager

I also tried 32-bit versions: same problem.

One difference between these two versions is that 2.15.x installs with a standard Windows installer; 2.14 is just a zip file that contains the application and its supporting files, no installation. That might be related to the whole-system vs. app-only freezing, but in both cases the comparison doesn't proceed.

One other variable from when comparisons worked vs. when they did not is the processor. I believe I was running an Intel i7 when it used to work. Then this summer I got a new computer (Intel Core Ultra 5). My coworkers were also running newer computers...

I'm happy to provide further details!

[sdottaka]

I created a box.com account and installed Box Drive version 2.42.213, but for some reason the C:\Users\{username}\Box folder and the files I uploaded to box.com are not synchronized properly, so I cannot reproduce this problem. (Currently, the Box folder is empty.)

Generally, unless an application uses an extremely large amount of memory or resources, the OS should control it so that it does not hang up, and in most cases there is no problem with the application. I wonder if the same thing happens with other comparison applications?

The first difference between WinMerge version 2.14 and 2.15 and later that immediately comes to mind is that 2.15 and later use multiple CPUs to perform comparisons.

To determine whether this is affecting you, could you please set Number of CPU cores to use in the Compare/Folder category in the Options window to 1 as shown below?

[DTC-tobin]

It does indeed seem like using multiple cores is related to the problem.

I set the number of CPU cores to 1, and the compare went off fine.

I played around a little bit, and 2 to 7 cores mostly worked, 8 cores and more, not so much (on one test, 8 cores got through about 80% of the files and then stopped, though this also happened with 7 cores).

FWIW my PC has 14 cores and 18 logical processors.

I also did some more testing with just 1 core, and that seems to complete even after multiple runs. As above, comparisons complete with a few number of cores, but as I increase the number, success is uncertain.