diff --git a/proto-cuda/windows-miner/start-mining.ps1 b/proto-cuda/windows-miner/start-mining.ps1
index 2243d70a8..2028f84d5 100644
--- a/proto-cuda/windows-miner/start-mining.ps1
+++ b/proto-cuda/windows-miner/start-mining.ps1
@@ -68,6 +68,22 @@ $script:tick = 0                 # frame counter, drives the heartbeat marker
 $script:events = New-Object System.Collections.ArrayList
 $script:uploadOk = $true
 
+function Get-ExitCode($inst) {
+    $code = $null
+    try { $code = $inst.proc.ExitCode } catch { }
+    if ($null -eq $code -and $inst.log -and (Test-Path $inst.log)) {
+        try {
+            $fs = New-Object IO.FileStream($inst.log, [IO.FileMode]::Open, [IO.FileAccess]::Read, [IO.FileShare]::ReadWrite)
+            $len = $fs.Length; $n = [Math]::Min($len, 4096); $fs.Seek(-$n, [IO.SeekOrigin]::End) | Out-Null
+            $b = New-Object byte[] $n; [void]$fs.Read($b, 0, $n); $fs.Close()
+            $tail = [Text.Encoding]::UTF8.GetString($b)
+            if ($tail -match 'exiting with code (\d+)') { $code = [int]$Matches[1] }
+            elseif ($tail -match 'SEED CHANGE') { $code = 42 }
+        } catch { }
+    }
+    return $code
+}
+
 function Log([string]$msg) {
     $line = "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') $msg"
     if (-not $script:dashOn) { Write-Host $line }
@@ -316,6 +332,7 @@ function Start-Miner($v, $inst) {
     }
     Set-Content -Path $inst.log -Value "igneum-mine-test $($inst.label) $machine $(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') node $nodeUrl run $($inst.runId) start $($inst.starts)"
     $inst.proc = Start-Process -FilePath $miner -ArgumentList $margs -WorkingDirectory $(if ($v.name -eq 'amd') { Join-Path $root 'proto-opencl' } else { $root }) -RedirectStandardOutput $inst.log -RedirectStandardError $inst.err -NoNewWindow -PassThru
+    if ($inst.proc) { $null = $inst.proc.Handle }   # without touching Handle, ExitCode comes back empty after the process ends
     $inst.startedAt = Get-Date
     Log "$($inst.label) started (pid $($inst.proc.Id)): `"$miner`" $($margs -join ' ')  -> $($inst.log)"
 }
@@ -832,7 +849,7 @@ try {
         foreach ($v in @($vendors.Values)) {
             $seedChange = $false
             foreach ($inst in $v.instances) {
-                if ($inst.proc -and $inst.proc.HasExited -and $inst.proc.ExitCode -eq 42) { $seedChange = $true }
+                if ($inst.proc -and $inst.proc.HasExited -and (Get-ExitCode $inst) -eq 42) { $seedChange = $true }
             }
             if ($seedChange) {
                 # The whole vendor group restarts: the worker exe cannot be rebuilt while another identity still runs it
@@ -861,7 +878,7 @@ try {
             foreach ($inst in $v.instances) {
                 if ($inst.proc -and $inst.proc.HasExited -and -not $inst.restartAt) {
                     $inst.restarts += 1
-                    $inst.exitCode = $inst.proc.ExitCode
+                    $inst.exitCode = Get-ExitCode $inst
                     $inst.restartAt = (Get-Date).AddSeconds(10)
                     Log "$($inst.label): miner exited unexpectedly with code $($inst.exitCode); restarting in 10 s (restart $($inst.restarts))"
                     Add-Event "$($v.card) miner $($inst.index) stopped (code $($inst.exitCode)), restarting in 10 s" 'error'