Windows freezes periodically while using Synergy

[ironica 0]

So I've been using Synergy for many years, primarily to connect two computers: a Linux desktop running various versions of Kubuntu (14, 16, 18, 20, 22) and a Windows laptop running first Windows 10, and now Windows 11. I always run the Linux desktop as the Synergy server, and the Windows laptop as the Synergy client. My keyboard and mouse are physically connected to the Linux desktop, and I use those to control the Windows laptop via Synergy. (Normally the laptop lid is closed and I have a 4K monitor plugged into it, which is how I see what's on the Windows laptop.)

I was using Synergy 1.14.6 until yesterday (same version on both computers). I updated to Windows 11 a few months ago. Everything was fine with Windows 11 for a while, but on June 16 I started noticing an issue that would occur: Whenever I was playing a game on the laptop (again, controlled via Synergy through the Linux desktop), occasionally the screen image and mouse cursor would freeze. The freeze would last anywhere from 1 to ~15 seconds, and in all cases, the screen and mouse would unfreeze and everything would return to normal. Never once since this began has the Windows machine experienced a system crash or BSOD or anything like that. Also, during the freezes, the Linux machine is normally responsive and appears to have no issues. If I close Synergy and control the laptop directly, using its own mouse and keyboard, the issue does not occur.

I tried all the usual things on the Windows machine: reinstalling graphics drivers, disabling excess system services, etc. Nothing helped. I tested various different games from different companies (primarily I play Blizzard games, e.g. WoW and Diablo, but I also play other stuff via Steam or Epic). The issue only occurred while playing games, not while doing anything else (e.g. watching YouTube videos). (I don't really use the laptop for anything besides games.) The games' logic continues to *run* while the freezes occur, meaning that I frequently end up getting killed or running off a cliff, which makes it difficult to play.

Eventually, yesterday, I tried updating to the latest Synergy 3 version (v3.0.72.1-rc1) on both the Linux desktop and Windows laptop to see if that would make any difference. It has not; the issue occurs with the same frequency as before. (I do want to say that Synergy 3 is a much friendlier and easy to use version of the program; it Just Worked™!) I tried monitoring the logfiles to see if anything was occurring at the moment the freeze started, but nothing does; for example, I noticed a freeze just now at precisely 11:15:20 (local time), which lasted for about 13 seconds. The Linux Synergy client log shows nothing until 11:15:33, at which point it prints:

synergy-core [2023-07-10T11:15:33] - NOTE - client "df580058e54fad0610fc484cb9a4e014ad812d17b08523bc1aa5a992c457219a" is dead

The Windows Synergy client log also shows nothing at 11:15:20, but at 11:15:33 it says it disconnected from the server, and then there are several reconnection messages over the next second, at which point everything went back to normal.

I've seen other discussions of a similar issue, which suggest things ilke disabling copy/paste or TLS. I'll try those and report back with results. If anyone has any other suggestions, I'm all ears. Thanks!

[ironica 0]

Something I forgot to include: The issue occurs sporadically, sometimes multiple times per minute, sometimes every several minutes. I've seen it go as long as 10-15 minutes between occurrences, but never really longer than that. It doesn't seem to correlate to anything I'm doing; it can occur when I'm sitting still, not using the keyboard and mouse, or when I'm actively playing the game.

[ironica 0]

Ok, so I tried disabling copy/paste; no effect, the issue still occurs. Then I tried disabling TLS; no effect, the issue still occurs.

I'm out of ideas at this point. (I forgot to mention that I also tried looking at CPU/GPU temperatures and the Event Viewer in Windows to see if there was anything there, but to no avail. The temperatures are not abnormally high and there was nothing of note in the Event Viewer. I will reiterate that the issue only occurs when Synergy is running.)

[Buffox 0]

Having exactly the same problem which just started in the last few days! Wondering if it's maybe a windows update?

[ironica 0]

Update: A friend who had had issues with Synergy causing freezes in the past suggested plugging my mouse into a USB 2.0 port (on the Linux desktop) instead of a USB 3.0 port. I tried that and it seemed to help quite a bit, but not completely; I played a game for over an hour before the first freeze happened, and it only lasted 1-2 seconds. Since then I've had numerous freezes but none have lasted longer than 5 seconds. It's unclear to me why this would make a difference (and specifically that difference) but I thought I'd add it.

5 hours ago, Buffox said:

Having exactly the same problem which just started in the last few days! Wondering if it's maybe a windows update?

There were a couple of Windows updates right before the problem started; specifically KB5027119 and KB5027231. The update descriptions are, of course, vague (thanks, Microsoft), so there's no telling if they caused the problem. Rolling them back was not an option (that was the first thing I checked). Can you check your update history and see if you had either of those recently?

[ironica 0]

Another update: I switched mice, from a fancy high-end gaming mouse (Logitech G502) to a low-end cheap mouse (Logitech M100). The issue hasn't occurred since. Still using the USB 2.0 port.

I suppose it's possible there was some USB driver update, either on the Linux or Windows box; or something degraded within the G502 itself; or something, that was causing occasional communications errors that made Windows freeze up.