diff --git a/util/iocommand.go b/util/iocommand.go
index 406e98f..0433446 100644
--- a/util/iocommand.go
+++ b/util/iocommand.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"os"
 	"os/exec"
 	"syscall"
 )
@@ -88,9 +89,23 @@ func (c *IOCommand) Read(buf []byte) (n int, err error) {
 
 func (c *IOCommand) doWait() (err error) {
 	waitErr := c.Cmd.Wait()
-	waitStatus := c.Cmd.ProcessState.Sys().(syscall.WaitStatus) // Fail hard if we're not on UNIX
+	var wasUs bool = false
+	var waitStatus syscall.WaitStatus
+	if c.Cmd.ProcessState == nil {
+		fmt.Fprintf(os.Stderr, "util.IOCommand: c.Cmd.ProcessState is nil after c.Cmd.Wait()\n")
+	}
+	if c.Cmd.ProcessState != nil {
+		sysSpecific := c.Cmd.ProcessState.Sys()
+		var ok bool
+		waitStatus, ok = sysSpecific.(syscall.WaitStatus)
+		if !ok {
+			fmt.Fprintf(os.Stderr, "util.IOCommand: c.Cmd.ProcessState.Sys() could not be converted to syscall.WaitStatus: %T\n", sysSpecific)
+			os.Stderr.Sync()
+			panic(sysSpecific) // this can only be true if we are not on UNIX, and we don't support that
+		}
+		wasUs = waitStatus.Signaled() && waitStatus.Signal() == syscall.SIGTERM // in Close()
+	}
 
-	wasUs := waitStatus.Signaled() && waitStatus.Signal() == syscall.SIGTERM // in Close()
 	if waitErr != nil && !wasUs {
 		err = IOCommandError{
 			WaitErr: waitErr,