On October 3, 2026, I discovered a leftover RobloxStudioBeta.exe process consuming approximately 68% of my total CPU while no Studio window was visible. Its matching log shows that Studio had destroyed its main window and reached application shutdown approximately six hours earlier. The process continued running until it was manually terminated.
Closing the studio session from task manager reduced CPU usage from 99% to 3%
I investigated because I had recently started experiencing lag/stutters in my PC. Ending the leftover Studio process substantially reduced background CPU usage.
-Report assisted by AI
Environment
| Component | Details |
|---|---|
| OS | Windows 11 Pro 25H2, build 26200.9457 |
| CPU | Intel Core i5-11400F, 6 cores / 12 logical processors |
| Installed RAM | 16 GB |
| GPU | NVIDIA GeForce RTX 2060 |
| NVIDIA driver | Windows driver version 32.0.16.1088; driver date July 22, 2026 |
| Studio version | 0.741.19.7411056 |
| Studio installation folder | %LOCALAPPDATA%\Roblox\Versions\version-76e1a02649ad4f35 |
| Executable | RobloxStudioBeta.exe |
| Process ID | 19704 |
| Process priority | Normal |
| Power plan | High performance |
Timeline
Local times are in UTC+04:00. The Studio log timestamps are UTC.
| Event | UTC + 4 | UTC |
|---|---|---|
| Process 19704 started | October 2, 22:17:06.922 | October 2, 18:17:06.922 |
| Main window destructor logged | October 2, 22:17:38.624 | October 2, 18:17:38.624 |
| AboutToQuit logged | October 2, 22:17:38.667 | October 2, 18:17:38.667 |
| End of main logged, return value 0 | October 2, 22:17:38.670 | October 2, 18:17:38.670 |
| Final timestamped log entry | October 2, 22:17:49.671 | October 2, 18:17:49.671 |
| Process discovered and manually terminated | October 3, approximately 04:24 | October 3, approximately 00:24 |
The exact termination time was not recorded separately. It preceded a Defender quick scan whose start event was recorded at 04:24:59 Dubai time. The process start time and process ID came from Windows, and the same process ID appears in the shutdown log, confirming the log belongs to the leftover process.
Actual Behavior And Measurements
The affected process had an empty MainWindowTitle. I was unaware that Studio was still running.
Two independent methods showed high CPU usage:
- The Windows process performance counter reported 818% before normalization. This counter sums CPU time across logical processors; with 12 logical processors, that is approximately 68.2% of total CPU capacity.
- An approximately eight-second sample of the process’s accumulated processor time measured 67.7% of total CPU capacity.
Additional measurements for PID 19704:
| Metric | Observed value |
|---|---|
| Private committed memory | Approximately 1,081.7 MiB |
| Resident working set | Approximately 9.7 MiB |
| Accumulated processor time | 182,999.203 seconds, summed across processor cores |
| Thread count | 43 |
| Handle count | 817 |
| Visible main window title | Empty |
Private committed memory and resident working set measure different things. The small working set does not mean the process had only allocated 9.7 MiB. These observations alone do not establish a memory leak.
Before termination, one system performance snapshot reported 100% CPU usage. After termination, a subsequent snapshot reported 16%. In the approximately ten-second process sample after termination, the largest individual accessible process was a Chrome process at 5.8% CPU. RobloxStudioBeta.exe was no longer running.
Approximately 6.7 GiB of physical memory remained available after termination. Both disks showed near-zero activity in that later snapshot. Disk activity and memory were measured at different instants, so these are observations rather than a controlled disk-performance comparison.
Matching Log Evidence
Log filename:
0.741.19.7411056_20261002T181707Z_Studio_A8C85_last.log
Selected excerpts from that log:
2026-10-02T18:17:38.364Z ... [FLog::CloseDataModel] Close DataModel Done!
2026-10-02T18:17:38.375Z ... [FLog::StudioChildProcessManager] About to close app, cleaning up child processes
2026-10-02T18:17:38.624Z ... [FLog::MainWindow] MainWindow::~MainWindow
2026-10-02T18:17:38.664Z ... Warning [FLog::QtUIThread] Task `LegacyRunInUIThreadWithQtContext-` scheduled after UI thread event loop has stopped
2026-10-02T18:17:38.664Z ... [FLog::UIThreadNotifier] Destructing UIThreadNotifier for process '19704' with id 'https://www.roblox.com-Studio'
2026-10-02T18:17:38.667Z ... [FLog::StudioApplicationState] AboutToQuit
2026-10-02T18:17:38.670Z ... [FLog::StudioMain] End of main. Return value 0. Has entered application scope: true
2026-10-02T18:17:38.671Z ... Warning [FLog::QtUIThread] Task `LegacyRunInUIThreadWithQtContext-` scheduled after UI thread event loop has stopped
2026-10-02T18:17:38.689Z ... Warning [FLog::RbxOtlpHttpExporter] OTLP export at concurrency cap - dropping batch
2026-10-02T18:17:40.759Z ... [FLog::Output] About to exit the application, doing cleanup.
2026-10-02T18:17:40.759Z ... [DFLog::StudioPerformanceMeasurementsSummary] StudioPerformanceMeasurements summary for StudioClose: 3297ms
2026-10-02T18:17:47.430Z ... [DFLog::HttpTraceError] CURLOPT_ERRORBUFFER: Failed to connect to localhost port 58741 after 2238 ms: Error
2026-10-02T18:17:49.671Z ... [DFLog::HttpTraceError] CURLOPT_ERRORBUFFER: Failed to connect to localhost port 58741 after 4273 ms: Error
The ellipses omit the elapsed-time/thread/log-level fields; the message text and UTC timestamps are preserved. The log also records plugin unloading and aborted/failed HTTP requests during shutdown.
Reproduction Status
One leftover process was confirmed and investigated. A reliable reproduction sequence and occurrence frequency are not yet established. The user action that triggered shutdown in this particular session is unknown; the log establishes that shutdown began approximately 30 seconds after launch.
Suggested steps to test, not yet confirmed as a consistent reproduction:
- Launch Studio on this version.
- Close Studio normally.
- Check Task Manager for RobloxStudioBeta.exe after its window disappears.
- If it remains, measure CPU usage for at least ten seconds and preserve that session’s log.
- Repeat with third-party Studio plugins disabled to establish whether plugins affect the result.
The affected process has already been terminated, so a thread stack sample or process dump from that instance is unavailable. No live dump, CPU trace, or before/after Task Manager screenshots were captured.
Workaround Tested
Manually ending only the affected RobloxStudioBeta.exe process stopped the observed excessive CPU usage.
Attachments And Related Report
I have attached PRIVATE_Studio_0.741.19.7411056_20261002T181707Z.log in the staff-only section
Might be the same report (marked as Fixed): Studio hangs with high CPU usage when closing the program
Expected behavior
After the Studio window closes and application shutdown completes, RobloxStudioBeta.exe should exit and release its resources. It should not remain alive for hours and consume approximately two-thirds of total CPU capacity without a visible window.
A private message is associated with this bug report