diff --git a/pkg/proc/gdbserial/gdbserver.go b/pkg/proc/gdbserial/gdbserver.go
index a201e573..4fc4b4d9 100644
--- a/pkg/proc/gdbserial/gdbserver.go
+++ b/pkg/proc/gdbserial/gdbserver.go
@@ -135,6 +135,14 @@ type Thread struct {
 	setbp             bool // thread was stopped because of a breakpoint
 }
 
+// ErrBackendUnavailable is returned when the stub program can not be found.
+type ErrBackendUnavailable struct {
+}
+
+func (err *ErrBackendUnavailable) Error() string {
+	return "backend unavailable"
+}
+
 // gdbRegisters represents the current value of the registers of a thread.
 // The storage space for all the registers is allocated as a single memory
 // block in buf, the value field inside an individual gdbRegister will be a
@@ -392,6 +400,9 @@ func LLDBLaunch(cmd []string, wd string) (*Process, error) {
 
 		proc = exec.Command(debugserverExecutable, args...)
 	} else {
+		if _, err := exec.LookPath("lldb-server"); err != nil {
+			return nil, &ErrBackendUnavailable{}
+		}
 		port = unusedPort()
 		args := make([]string, 0, len(cmd)+3)
 		args = append(args, "gdbserver")
@@ -452,6 +463,9 @@ func LLDBAttach(pid int, path string) (*Process, error) {
 		}
 		proc = exec.Command(debugserverExecutable, "-R", fmt.Sprintf("127.0.0.1:%d", listener.Addr().(*net.TCPAddr).Port), "--attach="+strconv.Itoa(pid))
 	} else {
+		if _, err := exec.LookPath("lldb-server"); err != nil {
+			return nil, &ErrBackendUnavailable{}
+		}
 		port = unusedPort()
 		proc = exec.Command("lldb-server", "gdbserver", "--attach", strconv.Itoa(pid), port)
 	}
diff --git a/pkg/proc/gdbserial/rr.go b/pkg/proc/gdbserial/rr.go
index 78c0ab43..6fb42cbb 100644
--- a/pkg/proc/gdbserial/rr.go
+++ b/pkg/proc/gdbserial/rr.go
@@ -15,6 +15,10 @@ import (
 // Record uses rr to record the execution of the specified program and
 // returns the trace directory's path.
 func Record(cmd []string, wd string, quiet bool) (tracedir string, err error) {
+	if _, err := exec.LookPath("rr"); err != nil {
+		return "", &ErrBackendUnavailable{}
+	}
+
 	rfd, wfd, err := os.Pipe()
 	if err != nil {
 		return "", err
@@ -49,6 +53,10 @@ func Record(cmd []string, wd string, quiet bool) (tracedir string, err error) {
 // Replay starts an instance of rr in replay mode, with the specified trace
 // directory, and connects to it.
 func Replay(tracedir string, quiet bool) (*Process, error) {
+	if _, err := exec.LookPath("rr"); err != nil {
+		return nil, &ErrBackendUnavailable{}
+	}
+
 	rrcmd := exec.Command("rr", "replay", "--dbgport=0", tracedir)
 	rrcmd.Stdout = os.Stdout
 	stderr, err := rrcmd.StderrPipe()
diff --git a/service/debugger/debugger.go b/service/debugger/debugger.go
index 099ebaf2..a1c8791c 100644
--- a/service/debugger/debugger.go
+++ b/service/debugger/debugger.go
@@ -113,13 +113,13 @@ func (d *Debugger) Launch(processArgs []string, wd string) (proc.Process, error)
 	case "native":
 		return native.Launch(processArgs, wd)
 	case "lldb":
-		return gdbserial.LLDBLaunch(processArgs, wd)
+		return betterGdbserialLaunchError(gdbserial.LLDBLaunch(processArgs, wd))
 	case "rr":
 		p, _, err := gdbserial.RecordAndReplay(processArgs, wd, false)
 		return p, err
 	case "default":
 		if runtime.GOOS == "darwin" {
-			return gdbserial.LLDBLaunch(processArgs, wd)
+			return betterGdbserialLaunchError(gdbserial.LLDBLaunch(processArgs, wd))
 		}
 		return native.Launch(processArgs, wd)
 	default:
@@ -137,10 +137,10 @@ func (d *Debugger) Attach(pid int, path string) (proc.Process, error) {
 	case "native":
 		return native.Attach(pid)
 	case "lldb":
-		return gdbserial.LLDBAttach(pid, path)
+		return betterGdbserialLaunchError(gdbserial.LLDBAttach(pid, path))
 	case "default":
 		if runtime.GOOS == "darwin" {
-			return gdbserial.LLDBAttach(pid, path)
+			return betterGdbserialLaunchError(gdbserial.LLDBAttach(pid, path))
 		}
 		return native.Attach(pid)
 	default:
@@ -148,6 +148,19 @@ func (d *Debugger) Attach(pid int, path string) (proc.Process, error) {
 	}
 }
 
+var macOSBackendUnavailableErr = errors.New("debugserver or lldb-server not found: install XCode's command line tools or lldb-server")
+
+func betterGdbserialLaunchError(p proc.Process, err error) (proc.Process, error) {
+	if runtime.GOOS != "darwin" {
+		return p, err
+	}
+	if _, isUnavailable := err.(*gdbserial.ErrBackendUnavailable); !isUnavailable {
+		return p, err
+	}
+
+	return p, macOSBackendUnavailableErr
+}
+
 // ProcessPid returns the PID of the process
 // the debugger is debugging.
 func (d *Debugger) ProcessPid() int {