Annoying bugs in FileWatch system for unity

Hi Elpatrongames69 

Thanks for taking the time to report these issues. I reviewed one by one and here is the status of each issue:

Bugs for linux (ubuntu 20.04)

1. Workspace switching doesn’t trigger Unity recompile (needs Alt+Tab)
   • The behaviour is consistent with how Unity normally works: it recompiles when file changes are detected, and the editor regains focus. Changing the workspace can move Rider around without actually bringing Unity to the foreground, whereas Alt+Tab explicitly focuses Unity, so Unity starts compiling.
   • As a workaround, you make sure that Automatically refresh assets in Unity is enabled in Settings | Languages & Frameworks | Unity Engine, so Unity gets a refresh request immediately on save, even if it still waits for focus to compile.
2. Compile trigger is delayed on Linux vs. Windows
   • Could you please confirm you’re on the latest Rider and Unity LTS versions, as they have multiple Unity‑integration fixes and performance work done.
   • Is your project on a network filesystem on Linux?
   • If the delay is reproducible and considerable (e.g. always 2–3 s on every save), it'll be very helpful if you could share a small reproduction project, Unity & Rider versions, OS info, and logs from both Rider and Unity.
3. Focus jumps from Rider to Unity when saving
   • This focus‑steal on save is a known Unity issue, tracked on Unity’s side and in Rider tickets (RIDER-58536 Application Focus Automatically Switches to Unity After Saving Changes to Script, RIDER-128610 Unity hijacks focus after saving file in Rider).
   • Unity has shipped fixes; if you're on an older version of Unity, please update it to resolve the problem.

Both Linux & Windows

1. “Filewatcher breaks” after refactors/new files; code analysis stops until Rider restarts.
   • There are some issues similar to what you describe, particularly around Unity project sync and new files:
     • RIDER-127402 Rider with Unity is just broken (Unity files are sometimes not part of the solution),
     • RIDER-130135 com.unity.ide.rider 3.0.37 RECENTLY introduced bug: new files interpreted as il code (bug in Rider Editor 3.0.37, fixed in 3.0.38),
     • RIDER-129477 "Refreshing solution in Unity Editor..." process (stuck “Refreshing solution in Unity Editor...”)

   • Please follow the next steps:

     1. Check Unity Rider package version in Unity’s Package Manager. If it’s 3.0.37, update to 3.0.38 (or later). This specifically fixes the “new files interpreted as IL / not in project” bug.
     2. Ensure Rider is 2025.2 or later; 2025.2+ contains several Unity integration fixes and performance improvements.
     3. If a file suddenly loses highlighting/usages:
        1.  Try in Unity → Preferences | Regenerate project files (brings missing files back into the .csproj) instead of immediately restarting Rider.
        2. Temporarily disable Automatically refresh assets in Unity in Rider; if the problem stops, that points to a Rider–Unity sync race, matching the existing tickets.
     4. If you store web front‑end code in the same repo please check in the Solution Explorer whether “New Files View” (repo view) is enabled; if yes, disable it and restart Rider so non‑solution folders (like node_modules) aren’t constantly indexed.

     If after all of this you still see all analysis drop out repeatedly until restart, please collect the logs in the following way:

     • Go to Help | Diagnostic tools | Choose Trace Scenarios 
     • Enable the Trace scenario for MultiPlatform
     • Reproduce the issue
     • Collect the full log bundle via Help | Collect Logs and Diagnostic Data, 
     • Disable Trace scenarios;
     • Attach the resulting log bundle to our server and share the ID or create a new Rider issue in our issue tracker.
2. Slow startup/sluggishness vs VS Code is a known area we’re actively working on; multiple issues are open or recently fixed, especially in 2025.x and upcoming 2026.x builds, e.g.:
   • RIDER-135656 Slow startup times on windows
   • RIDER-132897 Rider unresponsive on startup

In general and as a summary, to speed up Rider, you can:

• Update to the latest Rider and Unity LTS; update Unity Rider package to 3.0.38+.
• In Rider:
  • Turn Unity Profiler integration off if you don’t use it.
  • Keep Automatically refresh assets in Unity on, unless you need to avoid Unity focus‑stealing (then turn it off as a trade‑off).
  • Ensure Automatically disable asset indexing for large solutions is on.
  • Turn off New Files View / repo view in Solution Explorer to avoid extra indexing.
• Temporarily disable GitHub Copilot and see if startup and random freezes improve; known issues show Copilot can cause Rider deadlocks in some setups.
• On Windows, add Defender (antivirus) exclusions for Rider’s install/caches and your Unity project.
• If it’s still bad, run Profile Slow Startup once and share the snapshot through our server (share the uploadID) or in a new Rider issue so we can see exactly what’s slow.

You also can subscribe to the mentioned tickets (if they are open and match your issue) to get further updates and upvote to increase its visibility.

Hi Monica , thank you for your help.

The workspace problem works correctly on Windows and Mac; I don't need to save anything, just changing the workspace triggers the compile on both Mac and Windows. However, it doesn't work on Linux.

I can't specify the compile trigger delay and reproduce steps because it doesn't always happen; it only occurs sometimes. It happens a maximum of a few times in 10 hours of continuous work. However, it might be something related to my system; I'm not sure.

The focus jump issue was my fault, sorry. It was caused by the auto-focus feature in a Gnome extension I was using. Removing it fixed it.

The filewatcher crashing issue unfortunately happens occasionally no matter what I do. Both Unity, Rider, and Unity's Rider plugin are using the latest LTS version. I will test it by disabling profiler integration.

I will also try the performance settings you suggested. Thank you very much.

Meanwhile, I switched to an M1 MacBook Air 16gb ram for development, and Rider feels much more stable here; I no longer experience performance issues. This could be due to the OS or the difference in hardware, I don't know.

For reference, here are my PC specs for Windows and Linux:

i5 11400f - GTX 1660 Super - 16 GB DDR4 RAM - around 10,000 read/write Kingston M2 SSD.

However, the FileWatch issue persists, even on the MacBook. I will test it with the new settings you suggested, and if it's not resolved, I will share the logs as you mentioned. Thank you.

Hello Elpatrongames69 

Thanks for replying and sharing these details. The problem should not be attached to the hardware, but rather something related to specific Linux distribution, libraries, extensions, etc. So please, if you experience the crash/freeze, collect the logs right after and upload them so we can review and find the root cause of this issue.

Have a nice day!