Windows 11 Explorer freez with NextCloud Client 33.0.0 to 35.0.0 - fixed with 35.0.1 (update)

Please share this with the developers on your github issue.

I don’t notice any changes in the client’s behavior. Client 33.0.7 is also affected. I’ve also updated the Github report.

I have an Windows 11 Laptop. The Nextcloud client launches when the system starts up and immediately renders Windows Explorer unusable, as it simply stops displaying anything. However, as soon as I close the Nextcloud client, everything goes back to normal.

I’m currently using version 33.0.7.

It must be down to the Nextcloud client, as I’ve only just installed Windows 11.

I don’t notice any changes in the client’s behavior. Client 34.0.1 is also affected. I’ve also updated the Github report.

With the 34.0.x client—and in some cases also the 33.0.x client—there’s currently a theory on GitHub regarding a different but similar issue, depending on the antivirus software used (problems with Microsoft Defender)!

Since the circumstances sound similar to what we’re experiencing, I wanted to quickly ask which antivirus programs you’re using.

I’m also using Microsoft Defender on the affected computer, as well as on another one that’s having issues after the update from 33 to 34—but that one doesn’t have VFS enabled.

The issue is still present in our environment with version 34.0.7.

Explorer freezes frequently, causing Nextcloud synchronization to stop or behave unpredictably. Sometimes it starts syncing again on its own after a while.

We use Trend Micro as our antivirus solution, and Microsoft Defender is disabled on the affected machines. Therefore, the problem does not seem to be limited to Defender-based systems.

Can you temporarily disable it and check if the freeze still happens? The antivirus does not log any suspected files or anything?

And with a smaller sync folder, you never see this problem? Or is the freeze just so short that you won’t notice?

tried disabling the antivirus, but the issue is still not resolved.

I then tried synchronizing a smaller amount of data, around 300 GB (I normally synchronize about 1 TB), and the problem does not occur. Therefore, I believe it is the same issue as before, related to the size of the synchronized data.

And you are not syncing your windows profile? So there might be a conflict when accessing specific files?

To push further, I’d try to see for e.g. a new user, just use a script to create a lot of files inside a folder structure. If it is just the number of files, you see perhaps that it start to freeze for 200k+ files. But such a procedure would be nice so that the issue can be easily reproduced and it won’t depend on you specific data.

Hi,

No, we are not syncing the Windows user profile. Our users access data stored on cloud storage through Nextcloud.

We tested both an External Storage Box setup and Group Folders, and the issue occurs in both cases.

With Group Folders, synchronization works normally up to around 300 GB. Once we exceed that size, the client starts to freeze and disconnect from synchronization. At that point, the dataset contains roughly 50,000 files.

We can reproduce the same behavior both when upgrading an existing Nextcloud client installation and when performing a completely clean installation, which suggests the issue is not related to the Windows profile, a specific storage backend, or leftover client configuration.

Client 35.0.0 is also affected (with server 35.0.2). I’ve also updated the Github report.

Good news. For me, the problem—at least on Windows 11 with VFS enabled and a large number of files—seems to have been fixed with Client 35.0.1. There are still occasional minor lags, but they’re in the millisecond range, so they’re only noticeable when running scripts or when I habitually press the Enter key quickly—for example, in the save dialog. I’ve been testing it for 3 days now.