diff --git a/runtime/src/autocompile.c b/runtime/src/autocompile.c
index 998bb77d..b8ebf17c 100644
--- a/runtime/src/autocompile.c
+++ b/runtime/src/autocompile.c
@@ -532,9 +532,16 @@ int autocompile_request(void) {
     SetEnvironmentVariableA("PSX_OVERLAY_LIVE_AUTOCOMPILE", "1");
 
     /* cmd.exe /C resolves the command via PATH and supports the relative
-     * paths in the configured line (cwd = project root). */
+     * paths in the configured line (cwd = project root). The WHOLE command is
+     * wrapped in one extra pair of quotes: when the line after /C BEGINS with
+     * a quote and contains further quotes (a quoted interpreter path plus
+     * quoted args), cmd.exe strips the first and last quote characters and
+     * mangles the line ("The filename, directory name, or volume label syntax
+     * is incorrect" — every autocompile run failed and the reshard silently
+     * never happened). With the outer quotes cmd strips exactly those two and
+     * executes the inner command verbatim. */
     char full[4200];
-    snprintf(full, sizeof(full), "cmd.exe /C %s", s_cmd);
+    snprintf(full, sizeof(full), "cmd.exe /C \"%s\"", s_cmd);
 
     STARTUPINFOA si;
     memset(&si, 0, sizeof(si));
diff --git a/tools/launch_tomba2_interp_perf.ps1 b/tools/launch_tomba2_interp_perf.ps1
index e7567113..ddcea7ca 100644
--- a/tools/launch_tomba2_interp_perf.ps1
+++ b/tools/launch_tomba2_interp_perf.ps1
@@ -85,8 +85,16 @@ foreach ($dir in @($stateDir, (Split-Path $capturePath -Parent), $runDir, $logDi
     New-Item -ItemType Directory -Force -Path $dir | Out-Null
 }
 
+# Windows Python EXPLICITLY (never unqualified 'python'): the game process
+# inherits whatever PATH the launching shell had, and an MSYS python first on
+# PATH cannot open the Windows-style script path — every autocompile run then
+# fails with "can't open file" and the reshard silently never happens.
+$windowsPython = Join-Path $env:LOCALAPPDATA 'Programs\Python\Python312\python.exe'
+if (-not (Test-Path -LiteralPath $windowsPython -PathType Leaf)) {
+    throw "Windows Python not found at $windowsPython (required for autocompile)."
+}
 $autoCompile = @(
-    'python', (Quote-ProcessArgument $compileTool),
+    (Quote-ProcessArgument $windowsPython), (Quote-ProcessArgument $compileTool),
     '--captures', (Quote-ProcessArgument $capturePath),
     '--game-toml', (Quote-ProcessArgument $gameConfig),
     '--recompiler', (Quote-ProcessArgument $recompiler),