diff --git a/keymatic.py b/keymatic.py
index 654b4a4..9db61d6 100755
--- a/keymatic.py
+++ b/keymatic.py
@@ -28,6 +28,8 @@ def getBuffer(p):
 def expect(p, s, t=0):
     b = ""
     while True:
+        if p.poll() is not None:
+            raise Exception("Can't read data: Process Terminated")
         b = b + getBuffer(p).decode()
         if s in b:
             return b