Whois.exe bug is fixed, but cursor agent still ultra slow

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

The agent slows down to a crawl after a very short time using Cursor. It behaves fine for a little bit, but then all local operations just stop working and constantly pop 3s+ errors.

I’m on the latest version, so the whois.exe bug is finally fixed, but the performance problem is absolutely not.

2026-09-14 14:53:55.394 [warning] [watchdog, LocalWriteExecutor] readText before write still not completed after 3000ms
2026-09-14 14:54:06.915 [warning] [watchdog, LocalWriteExecutor] permissionsService.shouldBlockWrite still not completed after 3000ms
2026-09-14 14:54:13.124 [info] [cursor-agent-exec] mount alias add kind=principal mountKey=t13930313-u371296559 alias=user
2026-09-14 14:54:36.101 [warning] [watchdog, LocalWriteExecutor] getBufferForWrite still not completed after 3000ms
2026-09-14 14:54:49.380 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms
2026-09-14 14:54:53.451 [info] [agent-store-sync] abf45726-c632-4483-bb4d-7644f63fa9da sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:55:01.707 [info] [agent-store-sync] 801c89c2-6fe0-43af-a10c-5fc0657e8ce6 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:55:31.621 [warning] [watchdog, LocalWriteExecutor] readText before write still not completed after 3000ms
2026-09-14 14:55:33.427 [info] [agent-store-sync] t13930313-u371296559 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:55:42.938 [warning] [watchdog, LocalWriteExecutor] permissionsService.shouldBlockWrite still not completed after 3000ms
2026-09-14 14:56:05.893 [warning] [watchdog, LocalWriteExecutor] getBufferForWrite still not completed after 3000ms
2026-09-14 14:56:19.619 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms
2026-09-14 14:56:44.391 [info] [agent-store-sync] abf45726-c632-4483-bb4d-7644f63fa9da sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:56:58.269 [warning] [watchdog, LocalWriteExecutor] readText before write still not completed after 3000ms
2026-09-14 14:57:03.903 [info] [agent-store-sync] 801c89c2-6fe0-43af-a10c-5fc0657e8ce6 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:57:11.356 [warning] [watchdog, LocalWriteExecutor] permissionsService.shouldBlockWrite still not completed after 3000ms
2026-09-14 14:57:28.934 [info] [agent-store-sync] t13930313-u371296559 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.
2026-09-14 14:57:42.889 [warning] [watchdog, LocalWriteExecutor] getBufferForWrite still not completed after 3000ms

Steps to Reproduce

Use agent for a while, have multiple agent windows

Expected Behavior

Cursor agent should not be bogged down by untraceable OS slowdowns

Operating System

Windows 10/11

Version Information

Version: 3.19.19 (system setup)
VS Code Extension API: 1.128.0
Commit: 6496ea8a068aebfcd21990e70ff522e9abf10c80
Date: 2026-09-08T16:25:33.352Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 42.10.0
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
xterm.js: 6.1.0-beta.291
OS: Windows_NT x64 10.0.26200

For AI issues: which model did you use?

Any

Does this stop you from using Cursor

Yes - Cursor is unusable

5

Hey, thanks for the report and the log lines, that really helps.

What you’re describing (LocalWriteExecutor ... still not completed after 3000ms) is a known issue on Windows that we’re tracking. In roughly versions 3.19.10 through 3.20.16, the agent’s local file operations could hang for tens of seconds. The fix shipped in 3.20.17.

The catch is that the log you attached was captured on 3.19.19, you can see that in Help > About: Version: 3.19.19 (system setup), commit 6496ea8a068a. It looks like you have two installs on the machine, a per-machine “system setup” one (3.19.x) and a newer per-user one, and the slow window is launching from the old install. So the “whois.exe bug is fixed” change hasn’t been applied in that window yet.

Please try this:

  1. In the slow window, open Help > About and check the version. If it’s 3.19.x, that’s the install you need to update.
  2. In the same window, run Help > Check for Updates and let it restart. If it doesn’t offer an update, uninstall that copy via Windows Settings > Apps > Cursor, then reinstall from Cursor · Download.
  3. Open a new window and check Help > About again. It should be 3.20.17 or newer.
  4. Run an agent task that edits multiple files.

The agent-store-sync ... not authorized to use cloud agents in this team lines in the log are a separate thing, your access to cloud agents is restricted at the team level, and it’s not related to the slowdown.

If after updating you’re on 3.20.17+ and the file steps still hang for more than a minute, send your version and one Request ID right corner of the chat > Copy Request ID and we’ll dig in.

6

Ha, that’s a big fail on my part. I swear I installed the latest one… then clicked on the taskbar icon to launch it… which apparently goes to some other system 3.19 one. Wow.

That said, I’m working with the new version and it’s still doing it:
2026-09-15 02:05:12.168 [info] [cursor-agent-exec] mount alias add kind=principal mountKey=t13930313-u371296559 alias=user

2026-09-15 02:06:35.111 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:06:46.158 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:06:50.736 [info] [agent-store-sync] a1262fcf-39a0-440b-91e0-70437254f148 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.

2026-09-15 02:08:51.096 [info] [agent-store-sync] a1262fcf-39a0-440b-91e0-70437254f148 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.

2026-09-15 02:09:21.299 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:09:32.190 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:10:11.923 [info] [cursor-agent-exec] mount alias add kind=principal mountKey=t13930313-u371296559 alias=user

2026-09-15 02:10:41.063 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:10:51.401 [info] [agent-store-sync] a1262fcf-39a0-440b-91e0-70437254f148 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.

2026-09-15 02:12:50.565 [info] [agent-store-sync] a1262fcf-39a0-440b-91e0-70437254f148 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.

2026-09-15 02:14:43.081 [info] [agent-store-sync] a1262fcf-39a0-440b-91e0-70437254f148 sync failed: [unauthenticated] You are not authorized to use cloud agents in this team. Please contact your team admin.

2026-09-15 02:15:11.857 [info] [cursor-agent-exec] mount alias add kind=principal mountKey=t13930313-u371296559 alias=user

2026-09-15 02:15:18.528 [warning] [watchdog, LocalWriteExecutor] permissionsService.shouldBlockWrite still not completed after 3000ms

2026-09-15 02:15:24.219 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

2026-09-15 02:15:35.801 [warning] [watchdog, LocalWriteExecutor] writeFile still not completed after 3000ms

Version: 3.20.21 (user setup)
VS Code Extension API: 1.128.0
Commit: f09fca384ceca23f7bf21f9c23655b162641d740
Date: 2026-09-13T19:02:51.781Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 42.10.0
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
xterm.js: 6.1.0-beta.291
OS: Windows_NT x64 10.0.26200

Request id: 7463ebcd-9928-4582-82c8-c21d5312e409

7

It actually doesn’t feel like it gets stuck now, and I only see the WriteFile taking more than 3s when it’s actively coding, so perhaps the issue is much improved!

8

Sounds like this is what we needed. The key thing is that the short freezes you were seeing on 3.20.21 are gone.

About what’s left: the watchdog line about writeFile ... not completed after 3000ms is just a log that a specific step took more than 3 seconds. It doesn’t mean everything is stuck. Seeing these lines occasionally during active coding, especially on machines with corporate security software like Zscaler or EDR that scans every file operation, is within expectations. The bad scenario we were fixing is when steps hang for tens of seconds or even minutes. That shouldn’t happen on the fixed build.

So if you hit a real freeze again for a minute or more, send the version and one Request ID (three dots on the message > Copy Request ID), and we’ll dig deeper. For now, it looks like everything’s normal.

Regarding agent-store-sync ... not authorized to use cloud agents in this team, that’s a separate issue. Your access to cloud agents is limited at the team level, and it’s not related to speed.