Browser/Computer Use runtime won't start

“MXC launcher: cannot locate required Windows platform directory: HRESULT 0x80070003”

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Fading. 2 reports and thumbs-up in the last 7 days and 4 the week before, down from 34 a week at the mid-October peak.

8 bugs in this theme

MXC launcher browser init failureNo workaround yet38 people
Browser control fails at startup with sandbox-exec TIOCSTI errorNo workaround yet19 people
MXC sandbox startup failureNo workaround yet11 people
Browser control fails with trusted Node process exiting on WindowsNo workaround yet5 people
Computer use initialization failsNo workaround yet3 people
MXC launcher startup failureNo workaround yet3 people
Computer Use startup failureNo workaround yet2 people
Node REPL calls time outNo workaround yet2 people

What's included

Windows: MXC launcher reports CreateProcessSecurityEnvironment failed (HRESULT 0x80070020) or cannot locate required Windows platform directory (HRESULT 0x80070003)
Windows: 'trusted Node process exited unexpectedly; kernel reset' or 'failed to write kernel assets ... (os error 3)' on cua.getState() or @oai/sky init
Windows: 'windows sandbox failed: permission path cannot be represented losslessly' when initializing Computer Use or Chrome control
macOS: node_repl exits with code 65 and 'sandbox-exec: unbound variable: TIOCSTI' for in-app browser or @Chrome
Fails only in Dot-launched or Work Mode tasks while a local chat works

Not included

Sandboxed shell commands blocked by MXC error 1326 from an inaccessible mapped network drive
Browser tools that start but fail during page navigation or interaction

Original reports63, newest first

Nov 2, 2026CreateProcessSecurityEnvironment failed (0x80070020)On GitHub#58977
Oct 30, 2026Windows 26.1027.3384.0: node_repl minimal call times out after MCP reports readyOn GitHub#58282
Oct 28, 2026Windows app 26.1023.50603: Computer Use and shell fail to start with MXC 0x80070020 after full app restartOn GitHub#57652
Oct 26, 2026Error 0x80070020On GitHub#57069
Oct 25, 2026Windows app 26.1021.31345: Chrome and Computer Use startup fails with permission path cannot be represented losslesslyOn GitHub#56924
Oct 24, 2026Windows desktop: browser and computer-use initialization fail with kernel-assets path error (26.1007.9446.0)On GitHub#56747
Oct 19, 2026[Windows] Codex App sandbox fails to execute commands (HRESULT 0x80070020)On GitHub#55230
Oct 19, 2026The retry still fails with MXC error 0x80070020On GitHub#55224
Oct 18, 2026Windows: browser tools fail with MXC CreateProcessSecurityEnvironment error 0x80070020On GitHub#55100
Oct 16, 2026ChatGPT Plus is unable to access AgentFire WordPress account when signed in with ChatGPT browser.On GitHub#54663

Show all 63Show only the newest 10

Oct 16, 2026Windows browser control fails before tab access: MXC launcher HRESULT 0x80070003On GitHub#54658
Oct 15, 2026Windows DOT fresh-task browser launch loses SystemDrive after update; local restricted browser worksOn GitHub#54477
Oct 15, 2026Windows: @Chrome fails with “MXC launcher: cannot locate required Windows platform directory” (HRESULT 0x80070003)On GitHub#54338
Oct 15, 2026Windows desktop 26.1007.71326: trusted Node worker exits despite successful direct runtime testsOn GitHub#54288
Oct 15, 2026Windows 26.1007.2314.0: CUA MXC known-folder failure and native Computer Use app-server not foundOn GitHub#54225
Oct 14, 2026Windows app 26.1007.9446.0: CUA MXC 0x80070003 persists; desktop applicability of #54027/#54069 and scoped diagnosticsOn GitHub#54157
Oct 14, 2026Windows Chrome control fails: MXC launcher cannot locate required Windows platform directory (0x80070003)On GitHub#54153
Oct 14, 2026Windows computer control fails to start: MXC launcher HRESULT 0x80070003On GitHub#54116
Oct 14, 2026[Windows] CUA initialization exits before inventory in ChatGPT 26.1007.9446.0On GitHub#54101
Oct 14, 2026Windows delegated CUA: MXC known-folder startup failure before Chrome inventoryOn GitHub#54085
Oct 14, 2026Windows Codex: browser control and node_repl fail with “trusted Node process exited unexpectedlyOn GitHub#53999
Oct 14, 2026[Windows][Codex Desktop] Dot-Delegated CUA Fails with HRESULT 0x80070003 — Missing SystemDrive Environment VariableOn GitHub#53970
Oct 14, 2026Windows: PC and browser control unavailable in Work — MXC 0x80070003On GitHub#53941
Oct 13, 2026Windows Chrome control fails before tab inspection: required platform directory missing (0x80070003)On GitHub#53813
Oct 13, 2026Windows CUA initialization still fails with MXC HRESULT 0x80070003 after desktop app reinstallOn GitHub#53783
Oct 13, 2026Computer and Browser Connection Issues with DotOn GitHub#53735
Oct 13, 2026[Windows] Codex/Dot Computer Use Fails — MXC Launcher HRESULT 0x80070003, CUA Timeouts, Browser Control UnavailableOn GitHub#53694
Oct 13, 2026Windows: delegated browser runtime fails before tab inventory (MXC 0x80070003, then trusted Node exits)On GitHub#53564
Oct 12, 2026Windows browser-control runtime exits before inventory: MXC launcher HRESULT 0x80070003On GitHub#53518
Oct 12, 2026Windows Dot Computer Use fails with MXC HRESULT 0x80070003; local chat worksOn the forum#1405767
Oct 12, 2026Windows: MXC startup fails with CreateProcessSecurityEnvironment error 0x80070002 after updateOn GitHub#53417
Oct 12, 2026[Windows] Work Mode browser CUA initialization still fails after app repair: MXC HRESULT 0x80070003On GitHub#53397
Oct 12, 2026MXC launcher: cannot locate required Windows platform directory: HRESULT 0x80070003.On GitHub#53356
Oct 11, 2026Windows 26.1007: native node_repl tools absent while browser CUA kernel fails in MXCOn GitHub#53255
Oct 11, 2026[Windows] Browser tools fail to initialize: MXC launcher HRESULT 0x80070003On GitHub#53188
Oct 11, 2026Windows 26.1007.21434: browser CUA launcher fails with HRESULT 0x80070003; desktop runtime not exposedOn GitHub#53130
Oct 10, 2026Windows Computer Use cannot initialize: failed to write kernel assets (os error 3)On GitHub#52969
Oct 10, 2026Computer Use fails on Windows — HRESULT 0x80070003On GitHub#52858
Oct 10, 2026Windows browser control fails with MXC platform directory HRESULT 0x80070003 on Desktop 26.1007.2314.0On GitHub#52857
Oct 9, 2026Windows: Tool startup fails with CreateProcessSecurityEnvironment error 0x80070020On GitHub#52752
Oct 9, 2026Codex for Windows: sandbox and browser tools fail to startOn GitHub#52547
Oct 9, 2026Windows Dots: CUA MXC launcher fails with HRESULT 0x80070003 after direct shell recoveryOn GitHub#52407
Oct 8, 2026Windows: browser control trusted Node child exits before connecting to EdgeOn GitHub#52377
Oct 8, 2026files not processingOn GitHub#52042
Oct 4, 2026Codex Desktop on Windows selects MXC and fails before shell start when filesystem grants are present (0x80070002)On GitHub#50981
Oct 1, 2026Computer Use sandbox startup fails on macOS 14.3.1 with TIOCSTI in desktop 26.928.31416On GitHub#50150
Oct 1, 2026Codex App browser control crashes with TIOCSTI error on macOSOn GitHub#50070
Sep 30, 2026Computer Use fails on macOS 14.3.1: unbound variable TIOCSTIOn GitHub#49580
Sep 30, 2026no-active-thread-01a0f165-860b-7dc2-93f9-d169c324efa6On GitHub#49534
Sep 29, 2026macOS: Browser Use fails with sandbox-exec "unbound variable: TIOCSTI" (node_repl exit 65)On GitHub#49460
Sep 29, 2026Windows Computer Use node_repl exits before @oai/sky initialization: permission path cannot be represented losslesslyOn GitHub#49370
Sep 29, 2026[macOS Intel][Desktop 26.924.22138] Browser controller cannot start; bundled sandbox still fails with unbound TIOCSTIOn GitHub#49288
Sep 28, 2026[Windows][Codex Desktop 26.924] Node REPL times out on trivial code before browser accessOn GitHub#49077
Sep 27, 2026CUA fails on macOS 13.7.8: sandbox-exec rejects TIOCSTI with exit code 65On GitHub#48780
Sep 27, 2026Browser tools fail to start on macOS.On GitHub#48741
Sep 26, 2026# Codex macOS browser-control startup failureOn GitHub#48408
Sep 25, 2026Bug Report: Computer Use runtime crash on macOS Sonoma (TIOCSTI sandbox-exec error)On GitHub#48049
Sep 21, 2026Browser control fails on macOS 13.7.8: TIOCSTI sandbox errorOn GitHub#46951
Sep 18, 2026Browser control fails on macOS 14.1.2: sandbox-exec: unbound variable: TIOCSTIOn GitHub#46576
Sep 17, 2026macOS 14.3: browser and desktop control fail at startup with TIOCSTI errorOn GitHub#46212
Sep 16, 2026macOS: Codex browser control via Chrome extension fails at startup — node_repl exits (code 65) with sandbox-exec: unbound variable: TIOCSTIOn GitHub#45950
Sep 15, 2026Computer Use crashes with sandbox-exec TIOCSTI unbound variable (exit code 65) on macOSOn GitHub#45842
Sep 15, 2026Computer Use node_repl crashes on macOS with TIOCSTI errorOn GitHub#45767