Desktop app exits silently with code 3 when it cannot create its user-data files (no dialog, no log)

[PHSchr3ck3]

Environment

• DSH Desktop 0.2.1-rc.5, Windows 11 x64
• Per-user install: %LOCALAPPDATA%ProgramsDeepSeek Harness

Symptom

The desktop app stopped starting entirely. Double-clicking the exe produced no window, no dialog, no log entry and no files under %APPDATA%@deepseek-aidsh-desktop; the process exited immediately with exit code 3. --dump-config is refused for the managed desktop profile, so there was no user-facing way to find out what failed.

Evidence

Starting the exe with --enable-logging --log-file=<writable path> produced:

ERROR:chrome�rowserprocess_singleton_win.cc:318] Lock file can not be created: Zugriff verweigert (0x5)
Histogram: Chrome.ProcessSingleton.CreateLockFileWithTimeout.ErrorCode recorded 1 samples
5  -O   (1 = 100.0%)

The install folder carried this ACL at the time (Jeder = Everyone):

DeepSeek Harness  Jeder:(CI)(DENY)(DC)
                  S-1-4-1050771962-1020670054:(OI)(CI)(W,D,DC)
                  NT-AUTORITAETSYSTEM:(I)(OI)(CI)(F)
                  VORDEFINIERTAdministratoren:(I)(OI)(CI)(F)
                  PC<user>:(I)(OI)(CI)(F)
                  Verbindliche BeschriftungNiedrige Verbindlichkeitsstufe:(OI)(CI)(NW)

With that ACL in place the app could read anywhere but write only inside its own install folder. Verified by running the same binary with ELECTRON_RUN_AS_NODE=1 and a script writing to several paths: %USERPROFILE%, %APPDATA%, %TEMP% and ~/.dsh all returned EPERM, while the install folder succeeded.

Control tests:

• Same tree copied to a clean folder -> starts normally, creates cordis.yml and the Chromium profile.
• After removing the deny ACE and the foreign SID and resetting the integrity label to Medium (icacls ... /setintegritylevel (OI)(CI)M /T) -> the original install starts again.

Likely trigger

A third-party sandbox/security tool appears to have applied that ACL to the folder, so the permission state itself is environmental. The DSH-side bug is that this state fails completely silently.

Request

1. Surface startup failures: show a dialog and/or write a startup log entry when the user-data directory, the single-instance lock file or the profile composition fails, including the affected path and the OS error code.
2. Never exit with code 3 without any log artifact. A log written to a fallback location such as %TEMP% would have made this diagnosable in seconds.
3. Optionally detect a Low-integrity/AppContainer ACL on the install folder and warn the user instead of dying.

Workaround for other users

icacls "<install dir>" /remove:d "*S-1-1-0" /T /C
icacls "<install dir>" /remove:g "*S-1-4-*" /T /C
icacls "<install dir>" /setintegritylevel (OI)(CI)M /T /C