Error 22 after restart of Langflow (flow build failed - failed to fetch)

[curious-city]

Bug Description

My Langflow-Flow works perfectly after first launch of Langflow (after system startup).
As soon as I end Langflow and open it up again (which is way faster than the initial startup of the program) I get an error message when trying to run my flow:

Error while updating the Component

• [Errno 22] Invalid argument
• Flow build failed - Failed to fetch

-> Screenshot (error message): https://postimg.cc/Lq07w89W
-> Screenshot (my Langflow flow): https://postimg.cc/s1bKyKXv

Since the flow works just fine at first, it must be an issue inside Langflow itself and not the flow.
Note: Ollama is part of this flow and runs in the background but restarting Ollama doesn't make any difference either (according to the console, Ollama works just fine on localhost the entire time, so most likely it is a Langflow issue and not a Ollama issue).

Even ending the Langflow task via TaskManager doesn't resolve the issue. Only a restart of the PC works as solution, well more like a workaround.

Looking forward to a fix since only using my flow once a day (or once a PC startup) is not a permanent solution. And I don't want to run the LLM or Langflow the entire day without using it.

Langflow: v.1.6.2
Python: v.3.14.0

The logfile doesn't say much but I will post it anyway:
No idea why the logfile gets mangled up inside the spoiler this time, last time each line was displayed separately. Sorry for that. Just pay attention to the last two lines, I think the rest is not important at all.

Logfile

[2025-12-10][22:40:30][INFO] Window close requested - exiting application [2025-12-10][22:40:30][INFO] Exit event triggered [2025-12-10][22:40:30][INFO] 🧹 [CLEANUP] Killing processes on Langflow port 7860... [2025-12-10][22:40:30][INFO] [KILL_PROCESS] Trying to kill processes on port 7860 [2025-12-10][22:40:30][INFO] [KILL_PROCESS] No process found on port 7860 [2025-12-10][22:40:30][INFO] ✅ [CLEANUP] Processes on port 7860 killed successfully [2025-12-10][22:40:30][INFO] ℹ️ [CLEANUP] No MCP server ports registered to clean up [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Cleanup completed: 1 ports killed [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Successfully killed ports: [7860] [2025-12-10][22:40:30][INFO] Exit event triggered [2025-12-10][22:40:30][INFO] 🧹 [CLEANUP] Killing processes on Langflow port 7860... [2025-12-10][22:40:30][INFO] [KILL_PROCESS] Trying to kill processes on port 7860 [2025-12-10][22:40:30][INFO] [KILL_PROCESS] No process found on port 7860 [2025-12-10][22:40:30][INFO] ✅ [CLEANUP] Processes on port 7860 killed successfully [2025-12-10][22:40:30][INFO] ℹ️ [CLEANUP] No MCP server ports registered to clean up [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Cleanup completed: 1 ports killed [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Successfully killed ports: [7860] [2025-12-10][22:40:30][INFO] Exit event triggered [2025-12-10][22:40:30][INFO] 🧹 [CLEANUP] Killing processes on Langflow port 7860... [2025-12-10][22:40:30][INFO] [KILL_PROCESS] Trying to kill processes on port 7860 [2025-12-10][22:40:30][INFO] [KILL_PROCESS] No process found on port 7860 [2025-12-10][22:40:30][INFO] ✅ [CLEANUP] Processes on port 7860 killed successfully [2025-12-10][22:40:30][INFO] ℹ️ [CLEANUP] No MCP server ports registered to clean up [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Cleanup completed: 1 ports killed [2025-12-10][22:40:30][INFO] 🎯 [CLEANUP] Successfully killed ports: [7860] [2025-12-10][22:40:35][INFO] Application built successfully [2025-12-10][22:40:35][INFO] Running application... [2025-12-10][22:40:35][INFO] Setting up application... [2025-12-10][22:40:35][INFO] Killing any existing processes on Langflow port before startup [2025-12-10][22:40:35][INFO] 🧹 [CLEANUP] Killing processes on Langflow port 7860... [2025-12-10][22:40:35][INFO] [KILL_PROCESS] Trying to kill processes on port 7860 [2025-12-10][22:40:35][INFO] [KILL_PROCESS] No process found on port 7860 [2025-12-10][22:40:35][INFO] ✅ [CLEANUP] Processes on port 7860 killed successfully [2025-12-10][22:40:35][INFO] ℹ️ [CLEANUP] No MCP server ports registered to clean up [2025-12-10][22:40:35][INFO] 🎯 [CLEANUP] Cleanup completed: 1 ports killed [2025-12-10][22:40:35][INFO] 🎯 [CLEANUP] Successfully killed ports: [7860] [2025-12-10][22:40:35][INFO] Current window size after state restore: 1768x1297 [2025-12-10][22:40:35][INFO] Window size is unreasonable, calculating new size based on monitor [2025-12-10][22:40:35][INFO] Monitor size: 3840x2160 [2025-12-10][22:40:35][INFO] Setting window size to: 1400x1000 [2025-12-10][22:40:35][INFO] Using white Langflow tray icon at 30x30 [2025-12-10][22:40:35][INFO] Using main tray icon for 'Open Langflow' menu item [2025-12-10][22:40:35][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:35][INFO] Using 'regular' feedback icon for DARK system theme [2025-12-10][22:40:35][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:35][INFO] Using 'regular' book icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' discord icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' GitHub icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' X icon for DARK system theme [2025-12-10][22:40:36][INFO] Main tray icon created: white Langflow icon at 30x26 [2025-12-10][22:40:36][INFO] Refreshing tray icons for theme change - closing and recreating tray [2025-12-10][22:40:36][INFO] Removing existing tray icon (attempt 1) [2025-12-10][22:40:36][INFO] Creating new tray with current theme icons [2025-12-10][22:40:36][INFO] Using white Langflow tray icon at 30x30 [2025-12-10][22:40:36][INFO] Using main tray icon for 'Open Langflow' menu item [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' feedback icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' book icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' discord icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' GitHub icon for DARK system theme [2025-12-10][22:40:36][INFO] Windows theme detection: contains '0x0': true -> dark_mode: true [2025-12-10][22:40:36][INFO] Using 'regular' X icon for DARK system theme [2025-12-10][22:40:36][INFO] Main tray icon created: white Langflow icon at 30x26 [2025-12-10][22:40:36][INFO] Tray icons refreshed successfully - tray recreated (removed 1 instances) [2025-12-10][22:40:36][INFO] [CHECK_INSTALLED] Starting installation and terms check [2025-12-10][22:40:36][INFO] [Paths] UV directory already exists: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\uv" [2025-12-10][22:40:36][INFO] [Paths] All resolved paths: - home: "C:\\Users\\[USERNAME]" - base: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop" - user_data: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop" - env_deps: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop" - uv_folder: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\uv" - uv_binary: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\uv\\uv.exe" - venv: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\.langflow-venv" - venv_bin: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\.langflow-venv\\Scripts" - python: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\.langflow-venv\\Scripts\\python.exe" - langflow_bin: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\.langflow-venv\\Scripts\\langflow.exe" - site_packages: "C:\\Users\\[USERNAME]\\AppData\\Local\\com.LangflowDesktop\\.langflow-venv\\Lib/site-packages" - local_bin: "C:\\Users\\[USERNAME]\\.local/bin" - cache: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\cache" - data: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\data" - terms: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\data\\terms" - database: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\data\\database.db" - requirements_txt: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\data\\requirements.txt" - config_dat: "C:\\Users\\[USERNAME]\\AppData\\Roaming\\com.LangflowDesktop\\data\\config.dat" [2025-12-10][22:40:36][INFO] [CHECK_INSTALLED] Running Windows migration/backup check... [2025-12-10][22:40:36][INFO] [FIX_DB] ========== STARTING DATABASE MIGRATION CHECK ========== [2025-12-10][22:40:36][INFO] [FIX_DB] Data directory: C:\Users\[USERNAME]\AppData\Roaming\com.LangflowDesktop\data [2025-12-10][22:40:36][INFO] [FIX_DB] Migration flag path: C:\Users\[USERNAME]\AppData\Roaming\com.LangflowDesktop\data\.migration_completed [2025-12-10][22:40:36][INFO] [FIX_DB] Migration flag exists: true [2025-12-10][22:40:36][INFO] [FIX_DB] Backup flag found - backup already completed, skipping. [2025-12-10][22:40:36][INFO] [FIX_DB] Migration flag found - database migration already completed, skipping. [2025-12-10][22:40:36][INFO] [CHECK_INSTALLED] Migration/backup check completed [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Home directory: C:\Users\[USERNAME] [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Checking for UV at: C:\Users\[USERNAME]\AppData\Local\com.LangflowDesktop\uv\uv.exe [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] UV exists: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Checking for venv at: C:\Users\[USERNAME]\AppData\Local\com.LangflowDesktop\.langflow-venv [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Venv exists: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Venv directory has 9 entries [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Python executable: C:\Users\[USERNAME]\AppData\Local\com.LangflowDesktop\.langflow-venv\Scripts\python.exe [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Python exe exists: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Langflow executable: C:\Users\[USERNAME]\AppData\Local\com.LangflowDesktop\.langflow-venv\Scripts\langflow.exe [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Langflow exe exists: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Is fully installed: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Terms file exists: true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Terms file path: C:\Users\[USERNAME]\AppData\Roaming\com.LangflowDesktop\data\terms [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Ready to start (installed=true, terms=true): true [2025-12-10][22:40:36][INFO] 🔍 [CHECK_INSTALLED] Successfully emitted langflow-install: true [2025-12-10][22:40:36][INFO] [Health Check] Checking Langflow v1.6.2 [2025-12-10][22:40:36][INFO] Server is responding successfully [2025-12-10][22:40:36][INFO] [Health Check] Checking Langflow v1.6.2 [2025-12-10][22:40:36][INFO] Server is responding successfully

[2025-12-10][22:40:41][WARN] NewEvents emitted without explicit RedrawEventsCleared

[2025-12-10][22:40:41][WARN] RedrawEventsCleared emitted without explicit MainEventsCleared

Thanks!

Reproduction

1. Start Langflow (do whatever you want like running flows).
2. End Langflow.
3. Start Langflow up again without system reboot (flow doesn't work anymore)

Expected behavior

Flows running without issues even after restarting Langflow.

Who can help?

No response

Operating System

Windows 11 Enterprise x64 (25H2)

Langflow Version

1.6.2

Python Version

None

Screenshot

No response

Flow File

No response

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🔗 Similar Issues

Related Issues

• langflow-ai/langflow#10938
• langflow-ai/langflow#7132

🔗 Related PRs

#8233 - fix: Remove the dataframe output from structured [merged]
#8845 - docs: Repurpose Concepts section to focus on the visual editor and flows [merged]
#9133 - feat: introduce lfx package [merged]
#10204 - feat: update flows with agent with debug logs for chat history [merged]
#10922 - fix: correctly raise file not found errors in File GET endpoints [merged]

👤 Suggested Assignees

• curious-city
• ahango
• erichare
• aimurphy
• ogabrielluiz

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[Empreiteiro]

@curious-city This experience was related to a problem with our authentication cookie management.

In an environment with LANGFLOW_AUTO_LOGIN=False, the token lost its validity and although you could see the flow, it was not possible to execute it without first having to re-authenticate.

This problem started around version 1.6.0 and persisted until 1.6.9.

It has already been corrected in the main branch and in the next release branch, release-1.7.0.

Fix: #10528 #10527